feat: refactor immersion tracker queries and session word tracking

Add comprehensive query helpers for session deletion with word aggregate
refresh, known-words-per-session timeline, anime-level word summaries,
and trends dashboard aggregation. Track yomitanLookupCount in session
metrics and support bulk session operations.

src/config/resolve/immersion-tracking.ts

@@ -242,11 +242,7 @@ export function applyImmersionTrackingConfig(context: ResolveContext): void {
       }
 
       const dailyRollupsDays = asNumber(src.immersionTracking.retention.dailyRollupsDays);
-      if (
-        dailyRollupsDays !== undefined &&
-        dailyRollupsDays >= 0 &&
-        dailyRollupsDays <= 36500
-      ) {
+      if (dailyRollupsDays !== undefined && dailyRollupsDays >= 0 && dailyRollupsDays <= 36500) {
         retention.dailyRollupsDays = Math.floor(dailyRollupsDays);
       } else if (src.immersionTracking.retention.dailyRollupsDays !== undefined) {
         warn(
@@ -274,7 +270,11 @@ export function applyImmersionTrackingConfig(context: ResolveContext): void {
       }
 
       const vacuumIntervalDays = asNumber(src.immersionTracking.retention.vacuumIntervalDays);
-      if (vacuumIntervalDays !== undefined && vacuumIntervalDays >= 0 && vacuumIntervalDays <= 3650) {
+      if (
+        vacuumIntervalDays !== undefined &&
+        vacuumIntervalDays >= 0 &&
+        vacuumIntervalDays <= 3650
+      ) {
         retention.vacuumIntervalDays = Math.floor(vacuumIntervalDays);
       } else if (src.immersionTracking.retention.vacuumIntervalDays !== undefined) {
         warn(

src/core/services/immersion-tracker-service.test.ts

@@ -840,6 +840,59 @@ test('persists and retrieves minimum immersion tracking fields', async () => {
   }
 });
 
+test('recordYomitanLookup persists a dedicated lookup counter without changing annotation lookup metrics', async () => {
+  const dbPath = makeDbPath();
+  let tracker: ImmersionTrackerService | null = null;
+
+  try {
+    const Ctor = await loadTrackerCtor();
+    tracker = new Ctor({ dbPath });
+
+    tracker.handleMediaChange('/tmp/episode-yomitan.mkv', 'Episode Yomitan');
+    tracker.recordSubtitleLine('alpha beta gamma', 0, 1.2);
+    tracker.recordLookup(true);
+    tracker.recordYomitanLookup();
+
+    const privateApi = tracker as unknown as {
+      flushTelemetry: (force?: boolean) => void;
+      flushNow: () => void;
+    };
+    privateApi.flushTelemetry(true);
+    privateApi.flushNow();
+
+    const summaries = await tracker.getSessionSummaries(10);
+    assert.ok(summaries.length >= 1);
+    assert.equal(summaries[0]?.lookupCount, 1);
+    assert.equal(summaries[0]?.lookupHits, 1);
+    assert.equal(summaries[0]?.yomitanLookupCount, 1);
+
+    tracker.destroy();
+
+    const db = new Database(dbPath);
+    const sessionRow = db
+      .prepare('SELECT lookup_count, lookup_hits, yomitan_lookup_count FROM imm_sessions LIMIT 1')
+      .get() as {
+      lookup_count: number;
+      lookup_hits: number;
+      yomitan_lookup_count: number;
+    } | null;
+    const eventRow = db
+      .prepare(
+        'SELECT event_type FROM imm_session_events WHERE event_type = ? ORDER BY ts_ms DESC LIMIT 1',
+      )
+      .get(9) as { event_type: number } | null;
+    db.close();
+
+    assert.equal(sessionRow?.lookup_count, 1);
+    assert.equal(sessionRow?.lookup_hits, 1);
+    assert.equal(sessionRow?.yomitan_lookup_count, 1);
+    assert.equal(eventRow?.event_type, 9);
+  } finally {
+    tracker?.destroy();
+    cleanupDbPath(dbPath);
+  }
+});
+
 test('recordSubtitleLine persists counted allowed tokenized vocabulary rows and subtitle-line occurrences', async () => {
   const dbPath = makeDbPath();
   let tracker: ImmersionTrackerService | null = null;
@@ -1053,6 +1106,140 @@ test('subtitle-line event payload omits duplicated subtitle text', async () => {
   }
 });
 
+test('recordPlaybackPosition marks watched at 85% completion', async () => {
+  const dbPath = makeDbPath();
+  let tracker: ImmersionTrackerService | null = null;
+
+  try {
+    const Ctor = await loadTrackerCtor();
+    tracker = new Ctor({ dbPath });
+
+    tracker.handleMediaChange('/tmp/episode-85.mkv', 'Episode 85');
+    tracker.recordMediaDuration(100);
+    await waitForPendingAnimeMetadata(tracker);
+
+    const privateApi = tracker as unknown as {
+      db: DatabaseSync;
+      sessionState: { videoId: number } | null;
+    };
+    const videoId = privateApi.sessionState?.videoId;
+    assert.ok(videoId);
+
+    tracker.recordPlaybackPosition(84);
+    let row = privateApi.db
+      .prepare('SELECT watched FROM imm_videos WHERE video_id = ?')
+      .get(videoId) as { watched: number } | null;
+    assert.equal(row?.watched, 0);
+
+    tracker.recordPlaybackPosition(85);
+    row = privateApi.db
+      .prepare('SELECT watched FROM imm_videos WHERE video_id = ?')
+      .get(videoId) as { watched: number } | null;
+    assert.equal(row?.watched, 1);
+  } finally {
+    tracker?.destroy();
+    cleanupDbPath(dbPath);
+  }
+});
+
+test('deleteSession ignores the currently active session and keeps new writes flushable', async () => {
+  const dbPath = makeDbPath();
+  let tracker: ImmersionTrackerService | null = null;
+
+  try {
+    const Ctor = await loadTrackerCtor();
+    tracker = new Ctor({ dbPath });
+    tracker.handleMediaChange('/tmp/active-delete-test.mkv', 'Active Delete Test');
+
+    const privateApi = tracker as unknown as {
+      sessionState: { sessionId: number } | null;
+      flushTelemetry: (force?: boolean) => void;
+      flushNow: () => void;
+      queue: unknown[];
+    };
+    const sessionId = privateApi.sessionState?.sessionId;
+    assert.ok(sessionId);
+
+    tracker.recordSubtitleLine('before delete', 0, 1);
+    privateApi.flushTelemetry(true);
+    privateApi.flushNow();
+
+    await tracker.deleteSession(sessionId);
+
+    tracker.recordSubtitleLine('after delete', 1, 2);
+    privateApi.flushTelemetry(true);
+    privateApi.flushNow();
+
+    const db = new Database(dbPath);
+    const sessionCountRow = db
+      .prepare('SELECT COUNT(*) AS total FROM imm_sessions WHERE session_id = ?')
+      .get(sessionId) as { total: number };
+    const subtitleLineCountRow = db
+      .prepare('SELECT COUNT(*) AS total FROM imm_subtitle_lines WHERE session_id = ?')
+      .get(sessionId) as { total: number };
+    db.close();
+
+    assert.equal(sessionCountRow.total, 1);
+    assert.equal(subtitleLineCountRow.total, 2);
+    assert.equal(privateApi.queue.length, 0);
+  } finally {
+    tracker?.destroy();
+    cleanupDbPath(dbPath);
+  }
+});
+
+test('deleteVideo ignores the currently active video and keeps new writes flushable', async () => {
+  const dbPath = makeDbPath();
+  let tracker: ImmersionTrackerService | null = null;
+
+  try {
+    const Ctor = await loadTrackerCtor();
+    tracker = new Ctor({ dbPath });
+    tracker.handleMediaChange('/tmp/active-video-delete-test.mkv', 'Active Video Delete Test');
+
+    const privateApi = tracker as unknown as {
+      sessionState: { sessionId: number; videoId: number } | null;
+      flushTelemetry: (force?: boolean) => void;
+      flushNow: () => void;
+      queue: unknown[];
+    };
+    const sessionId = privateApi.sessionState?.sessionId;
+    const videoId = privateApi.sessionState?.videoId;
+    assert.ok(sessionId);
+    assert.ok(videoId);
+
+    tracker.recordSubtitleLine('before video delete', 0, 1);
+    privateApi.flushTelemetry(true);
+    privateApi.flushNow();
+
+    await tracker.deleteVideo(videoId);
+
+    tracker.recordSubtitleLine('after video delete', 1, 2);
+    privateApi.flushTelemetry(true);
+    privateApi.flushNow();
+
+    const db = new Database(dbPath);
+    const sessionCountRow = db
+      .prepare('SELECT COUNT(*) AS total FROM imm_sessions WHERE session_id = ?')
+      .get(sessionId) as { total: number };
+    const videoCountRow = db
+      .prepare('SELECT COUNT(*) AS total FROM imm_videos WHERE video_id = ?')
+      .get(videoId) as { total: number };
+    const subtitleLineCountRow = db
+      .prepare('SELECT COUNT(*) AS total FROM imm_subtitle_lines WHERE session_id = ?')
+      .get(sessionId) as { total: number };
+    db.close();
+
+    assert.equal(sessionCountRow.total, 1);
+    assert.equal(videoCountRow.total, 1);
+    assert.equal(subtitleLineCountRow.total, 2);
+    assert.equal(privateApi.queue.length, 0);
+  } finally {
+    tracker?.destroy();
+    cleanupDbPath(dbPath);
+  }
+});
+
 test('handleMediaChange links parsed anime metadata on the active video row', async () => {
   const dbPath = makeDbPath();
   let tracker: ImmersionTrackerService | null = null;
@@ -1821,3 +2008,49 @@ test('reassignAnimeAnilist deduplicates cover blobs and getCoverArt remains comp
     cleanupDbPath(dbPath);
   }
 });
+
+test('markActiveVideoWatched marks current session video as watched', async () => {
+  const dbPath = makeDbPath();
+  let tracker: ImmersionTrackerService | null = null;
+
+  try {
+    const Ctor = await loadTrackerCtor();
+    tracker = new Ctor({ dbPath });
+    tracker.handleMediaChange('/tmp/test-mark-active.mkv', 'Test Mark Active');
+    await waitForPendingAnimeMetadata(tracker);
+
+    const privateApi = tracker as unknown as {
+      db: DatabaseSync;
+      sessionState: { videoId: number; markedWatched: boolean } | null;
+    };
+    const videoId = privateApi.sessionState?.videoId;
+    assert.ok(videoId);
+
+    const result = await tracker.markActiveVideoWatched();
+    assert.equal(result, true);
+    assert.equal(privateApi.sessionState?.markedWatched, true);
+
+    const row = privateApi.db
+      .prepare('SELECT watched FROM imm_videos WHERE video_id = ?')
+      .get(videoId) as { watched: number } | null;
+    assert.equal(row?.watched, 1);
+  } finally {
+    tracker?.destroy();
+    cleanupDbPath(dbPath);
+  }
+});
+
+test('markActiveVideoWatched returns false when no active session', async () => {
+  const dbPath = makeDbPath();
+  let tracker: ImmersionTrackerService | null = null;
+
+  try {
+    const Ctor = await loadTrackerCtor();
+    tracker = new Ctor({ dbPath });
+    const result = await tracker.markActiveVideoWatched();
+    assert.equal(result, false);
+  } finally {
+    tracker?.destroy();
+    cleanupDbPath(dbPath);
+  }
+});

src/core/services/immersion-tracker-service.ts

@@ -6,6 +6,7 @@ import { getLocalVideoMetadata, guessAnimeVideoMetadata } from './immersion-trac
 import {
   pruneRawRetention,
   pruneRollupRetention,
+  runOptimizeMaintenance,
   runRollupMaintenance,
 } from './immersion-tracker/maintenance';
 import { Database, type DatabaseSync } from './immersion-tracker/sqlite';
@@ -60,6 +61,11 @@ import {
   getSessionEvents,
   getSessionSummaries,
   getSessionTimeline,
+  getSessionWordsByLine,
+  getTrendsDashboard,
+  getAllDistinctHeadwords,
+  getAnimeDistinctHeadwords,
+  getMediaDistinctHeadwords,
   getVocabularyStats,
   getWatchTimePerAnime,
   getWordAnimeAppearances,
@@ -69,6 +75,7 @@ import {
   upsertCoverArt,
   markVideoWatched,
   deleteSession as deleteSessionQuery,
+  deleteSessions as deleteSessionsQuery,
   deleteVideo as deleteVideoQuery,
 } from './immersion-tracker/query';
 import {
@@ -83,6 +90,7 @@ import {
   sanitizePayload,
   secToMs,
 } from './immersion-tracker/reducer';
+import { DEFAULT_MIN_WATCH_RATIO } from '../../shared/watch-threshold';
 import { enqueueWrite } from './immersion-tracker/queue';
 import {
   DEFAULT_BATCH_SIZE,
@@ -104,6 +112,7 @@ import {
   EVENT_SEEK_BACKWARD,
   EVENT_SEEK_FORWARD,
   EVENT_SUBTITLE_LINE,
+  EVENT_YOMITAN_LOOKUP,
   SOURCE_TYPE_LOCAL,
   SOURCE_TYPE_REMOTE,
   type ImmersionSessionRollupRow,
@@ -244,13 +253,21 @@ export class ImmersionTrackerService {
     );
 
     const retention = policy.retention ?? {};
-    const daysToRetentionMs = (value: number | undefined, fallbackMs: number, maxDays: number): number => {
+    const daysToRetentionMs = (
+      value: number | undefined,
+      fallbackMs: number,
+      maxDays: number,
+    ): number => {
       const fallbackDays = Math.floor(fallbackMs / 86_400_000);
       const resolvedDays = resolveBoundedInt(value, fallbackDays, 0, maxDays);
       return resolvedDays === 0 ? Number.POSITIVE_INFINITY : resolvedDays * 86_400_000;
     };
 
-    this.eventsRetentionMs = daysToRetentionMs(retention.eventsDays, DEFAULT_EVENTS_RETENTION_MS, 3650);
+    this.eventsRetentionMs = daysToRetentionMs(
+      retention.eventsDays,
+      DEFAULT_EVENTS_RETENTION_MS,
+      3650,
+    );
     this.telemetryRetentionMs = daysToRetentionMs(
       retention.telemetryDays,
       DEFAULT_TELEMETRY_RETENTION_MS,
@@ -321,6 +338,24 @@ export class ImmersionTrackerService {
     return getSessionTimeline(this.db, sessionId, limit);
   }
 
+  async getSessionWordsByLine(
+    sessionId: number,
+  ): Promise<Array<{ lineIndex: number; headword: string; occurrenceCount: number }>> {
+    return getSessionWordsByLine(this.db, sessionId);
+  }
+
+  async getAllDistinctHeadwords(): Promise<string[]> {
+    return getAllDistinctHeadwords(this.db);
+  }
+
+  async getAnimeDistinctHeadwords(animeId: number): Promise<string[]> {
+    return getAnimeDistinctHeadwords(this.db, animeId);
+  }
+
+  async getMediaDistinctHeadwords(videoId: number): Promise<string[]> {
+    return getMediaDistinctHeadwords(this.db, videoId);
+  }
+
   async getQueryHints(): Promise<{
     totalSessions: number;
     activeSessions: number;
@@ -343,6 +378,13 @@ export class ImmersionTrackerService {
     return getMonthlyRollups(this.db, limit);
   }
 
+  async getTrendsDashboard(
+    range: '7d' | '30d' | '90d' | 'all' = '30d',
+    groupBy: 'day' | 'month' = 'day',
+  ): Promise<unknown> {
+    return getTrendsDashboard(this.db, range, groupBy);
+  }
+
   async getVocabularyStats(limit = 100, excludePos?: string[]): Promise<VocabularyStatsRow[]> {
     return getVocabularyStats(this.db, limit, excludePos);
   }
@@ -437,11 +479,40 @@ export class ImmersionTrackerService {
     markVideoWatched(this.db, videoId, watched);
   }
 
+  async markActiveVideoWatched(): Promise<boolean> {
+    if (!this.sessionState) return false;
+    markVideoWatched(this.db, this.sessionState.videoId, true);
+    this.sessionState.markedWatched = true;
+    return true;
+  }
+
   async deleteSession(sessionId: number): Promise<void> {
+    if (this.sessionState?.sessionId === sessionId) {
+      this.logger.warn(`Ignoring delete request for active immersion session ${sessionId}`);
+      return;
+    }
     deleteSessionQuery(this.db, sessionId);
   }
 
+  async deleteSessions(sessionIds: number[]): Promise<void> {
+    const activeSessionId = this.sessionState?.sessionId;
+    const deletableSessionIds =
+      activeSessionId === undefined
+        ? sessionIds
+        : sessionIds.filter((sessionId) => sessionId !== activeSessionId);
+    if (deletableSessionIds.length !== sessionIds.length) {
+      this.logger.warn(
+        `Ignoring bulk delete request for active immersion session ${activeSessionId}`,
+      );
+    }
+    deleteSessionsQuery(this.db, deletableSessionIds);
+  }
+
   async deleteVideo(videoId: number): Promise<void> {
+    if (this.sessionState?.videoId === videoId) {
+      this.logger.warn(`Ignoring delete request for active immersion video ${videoId}`);
+      return;
+    }
     deleteVideoQuery(this.db, videoId);
   }
 
@@ -847,7 +918,7 @@ export class ImmersionTrackerService {
 
     if (!this.sessionState.markedWatched) {
       const durationMs = getVideoDurationMs(this.db, this.sessionState.videoId);
-      if (durationMs > 0 && mediaMs >= durationMs * 0.98) {
+      if (durationMs > 0 && mediaMs >= durationMs * DEFAULT_MIN_WATCH_RATIO) {
         markVideoWatched(this.db, this.sessionState.videoId, true);
         this.sessionState.markedWatched = true;
       }
@@ -915,6 +986,21 @@ export class ImmersionTrackerService {
     });
   }
 
+  recordYomitanLookup(): void {
+    if (!this.sessionState) return;
+    this.sessionState.yomitanLookupCount += 1;
+    this.sessionState.pendingTelemetry = true;
+    this.recordWrite({
+      kind: 'event',
+      sessionId: this.sessionState.sessionId,
+      sampleMs: Date.now(),
+      eventType: EVENT_YOMITAN_LOOKUP,
+      cardsDelta: 0,
+      wordsDelta: 0,
+      payloadJson: null,
+    });
+  }
+
   recordCardsMined(count = 1, noteIds?: number[]): void {
     if (!this.sessionState) return;
     this.sessionState.cardsMined += count;
@@ -981,6 +1067,7 @@ export class ImmersionTrackerService {
       cardsMined: this.sessionState.cardsMined,
       lookupCount: this.sessionState.lookupCount,
       lookupHits: this.sessionState.lookupHits,
+      yomitanLookupCount: this.sessionState.yomitanLookupCount,
       pauseCount: this.sessionState.pauseCount,
       pauseMs: this.sessionState.pauseMs,
       seekForwardCount: this.sessionState.seekForwardCount,
@@ -1080,6 +1167,7 @@ export class ImmersionTrackerService {
         this.db.exec('VACUUM');
         this.lastVacuumMs = nowMs;
       }
+      runOptimizeMaintenance(this.db);
     } catch (error) {
       this.logger.warn(
         'Immersion tracker maintenance failed, will retry later',
@@ -1108,6 +1196,7 @@ export class ImmersionTrackerService {
       cardsMined: 0,
       lookupCount: 0,
       lookupHits: 0,
+      yomitanLookupCount: 0,
       pauseCount: 0,
       pauseMs: 0,
       seekForwardCount: 0,

src/core/services/immersion-tracker/__tests__/query.test.ts

@@ -17,6 +17,7 @@ import {
   cleanupVocabularyStats,
   deleteSession,
   getDailyRollups,
+  getTrendsDashboard,
   getQueryHints,
   getMonthlyRollups,
   getAnimeDetail,
@@ -31,6 +32,7 @@ import {
   getVocabularyStats,
   getKanjiStats,
   getSessionEvents,
+  getSessionWordsByLine,
   getWordOccurrences,
   upsertCoverArt,
 } from '../query.js';
@@ -126,6 +128,7 @@ test('getSessionSummaries returns sessionId and canonicalTitle', () => {
     assert.equal(row.tokensSeen, 10);
     assert.equal(row.lookupCount, 2);
     assert.equal(row.lookupHits, 1);
+    assert.equal(row.yomitanLookupCount, 0);
   } finally {
     db.close();
     cleanupDbPath(dbPath);
@@ -165,6 +168,163 @@ test('getDailyRollups limits by distinct days (not rows)', () => {
   }
 });
 
+test('getTrendsDashboard returns chart-ready aggregated series', () => {
+  const dbPath = makeDbPath();
+  const db = new Database(dbPath);
+
+  try {
+    ensureSchema(db);
+    const stmts = createTrackerPreparedStatements(db);
+
+    const videoId = getOrCreateVideoRecord(db, 'local:/tmp/trends-dashboard-test.mkv', {
+      canonicalTitle: 'Trend Dashboard Test',
+      sourcePath: '/tmp/trends-dashboard-test.mkv',
+      sourceUrl: null,
+      sourceType: SOURCE_TYPE_LOCAL,
+    });
+    const animeId = getOrCreateAnimeRecord(db, {
+      parsedTitle: 'Trend Dashboard Anime',
+      canonicalTitle: 'Trend Dashboard Anime',
+      anilistId: null,
+      titleRomaji: null,
+      titleEnglish: null,
+      titleNative: null,
+      metadataJson: null,
+    });
+    linkVideoToAnimeRecord(db, videoId, {
+      animeId,
+      parsedBasename: 'trends-dashboard-test.mkv',
+      parsedTitle: 'Trend Dashboard Anime',
+      parsedSeason: 1,
+      parsedEpisode: 1,
+      parserSource: 'test',
+      parserConfidence: 1,
+      parseMetadataJson: null,
+    });
+
+    const dayOneStart = new Date(2026, 2, 15, 12, 0, 0, 0).getTime();
+    const dayTwoStart = new Date(2026, 2, 16, 18, 0, 0, 0).getTime();
+
+    const sessionOne = startSessionRecord(db, videoId, dayOneStart);
+    const sessionTwo = startSessionRecord(db, videoId, dayTwoStart);
+
+    for (const [
+      sessionId,
+      startedAtMs,
+      activeWatchedMs,
+      cardsMined,
+      wordsSeen,
+      tokensSeen,
+      yomitanLookupCount,
+    ] of [
+      [sessionOne.sessionId, dayOneStart, 30 * 60_000, 2, 100, 120, 8],
+      [sessionTwo.sessionId, dayTwoStart, 45 * 60_000, 3, 120, 140, 10],
+    ] as const) {
+      stmts.telemetryInsertStmt.run(
+        sessionId,
+        startedAtMs + 60_000,
+        activeWatchedMs,
+        activeWatchedMs,
+        10,
+        wordsSeen,
+        tokensSeen,
+        cardsMined,
+        0,
+        0,
+        yomitanLookupCount,
+        0,
+        0,
+        0,
+        0,
+        startedAtMs + 60_000,
+        startedAtMs + 60_000,
+      );
+
+      db.prepare(
+        `
+          UPDATE imm_sessions
+          SET
+            ended_at_ms = ?,
+            total_watched_ms = ?,
+            active_watched_ms = ?,
+            lines_seen = ?,
+            words_seen = ?,
+            tokens_seen = ?,
+            cards_mined = ?,
+            yomitan_lookup_count = ?
+          WHERE session_id = ?
+        `,
+      ).run(
+        startedAtMs + activeWatchedMs,
+        activeWatchedMs,
+        activeWatchedMs,
+        10,
+        wordsSeen,
+        tokensSeen,
+        cardsMined,
+        yomitanLookupCount,
+        sessionId,
+      );
+    }
+
+    db.prepare(
+      `
+        INSERT INTO imm_daily_rollups (
+          rollup_day, video_id, total_sessions, total_active_min, total_lines_seen,
+          total_words_seen, total_tokens_seen, total_cards
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+      `,
+    ).run(Math.floor(dayOneStart / 86_400_000), videoId, 1, 30, 10, 100, 120, 2);
+
+    db.prepare(
+      `
+        INSERT INTO imm_daily_rollups (
+          rollup_day, video_id, total_sessions, total_active_min, total_lines_seen,
+          total_words_seen, total_tokens_seen, total_cards
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+      `,
+    ).run(Math.floor(dayTwoStart / 86_400_000), videoId, 1, 45, 10, 120, 140, 3);
+
+    db.prepare(
+      `
+        INSERT INTO imm_words (
+          headword, word, reading, part_of_speech, pos1, pos2, pos3, first_seen, last_seen
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
+      `,
+    ).run(
+      '勉強',
+      '勉強',
+      'べんきょう',
+      'noun',
+      '名詞',
+      null,
+      null,
+      Math.floor(dayOneStart / 1000),
+      Math.floor(dayTwoStart / 1000),
+    );
+
+    const dashboard = getTrendsDashboard(db, 'all', 'day');
+
+    assert.equal(dashboard.activity.watchTime.length, 2);
+    assert.equal(dashboard.activity.watchTime[0]?.value, 30);
+    assert.equal(dashboard.progress.watchTime[1]?.value, 75);
+    assert.equal(dashboard.progress.lookups[1]?.value, 18);
+    assert.equal(
+      dashboard.ratios.lookupsPerHundred[0]?.value,
+      +((8 / 120) * 100).toFixed(1),
+    );
+    assert.equal(dashboard.animePerDay.watchTime[0]?.animeTitle, 'Trend Dashboard Anime');
+    assert.equal(dashboard.animeCumulative.watchTime[1]?.value, 75);
+    assert.equal(
+      dashboard.patterns.watchTimeByDayOfWeek.reduce((sum, point) => sum + point.value, 0),
+      75,
+    );
+  } finally {
+    db.close();
+    cleanupDbPath(dbPath);
+  }
+});
+
 test('getQueryHints reads all-time totals from lifetime summary', () => {
   const dbPath = makeDbPath();
   const db = new Database(dbPath);
@@ -238,6 +398,7 @@ test('getSessionSummaries with no telemetry returns zero aggregates', () => {
     assert.equal(row.tokensSeen, 0);
     assert.equal(row.lookupCount, 0);
     assert.equal(row.lookupHits, 0);
+    assert.equal(row.yomitanLookupCount, 0);
     assert.equal(row.cardsMined, 0);
   } finally {
     db.close();
@@ -292,6 +453,7 @@ test('getSessionSummaries uses denormalized session metrics for ended sessions w
     assert.equal(row.cardsMined, 5);
     assert.equal(row.lookupCount, 9);
     assert.equal(row.lookupHits, 6);
+    assert.equal(row.yomitanLookupCount, 0);
   } finally {
     db.close();
     cleanupDbPath(dbPath);
@@ -950,6 +1112,56 @@ test('getSessionEvents respects limit parameter', () => {
   }
 });
 
+test('getSessionWordsByLine joins word occurrences through imm_words.id', () => {
+  const dbPath = makeDbPath();
+  const db = new Database(dbPath);
+
+  try {
+    ensureSchema(db);
+    const stmts = createTrackerPreparedStatements(db);
+    const startedAtMs = Date.UTC(2025, 0, 1, 12, 0, 0);
+    const videoId = getOrCreateVideoRecord(db, '/tmp/session-words-by-line.mkv', {
+      canonicalTitle: 'Episode',
+      sourcePath: '/tmp/session-words-by-line.mkv',
+      sourceUrl: null,
+      sourceType: SOURCE_TYPE_LOCAL,
+    });
+    const { sessionId } = startSessionRecord(db, videoId, startedAtMs);
+    const lineId = Number(
+      db
+        .prepare(
+          `INSERT INTO imm_subtitle_lines (
+            session_id, event_id, video_id, anime_id, line_index, segment_start_ms, segment_end_ms, text, CREATED_DATE, LAST_UPDATE_DATE
+          ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+        )
+        .run(sessionId, null, videoId, null, 0, 0, 1000, '猫を見た', startedAtMs, startedAtMs)
+        .lastInsertRowid,
+    );
+    const wordId = Number(
+      db
+        .prepare(
+          `INSERT INTO imm_words (
+            headword, word, reading, pos1, pos2, pos3, part_of_speech, first_seen, last_seen, frequency
+          ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+        )
+        .run('猫', '猫', 'ねこ', null, null, null, null, startedAtMs, startedAtMs, 1)
+        .lastInsertRowid,
+    );
+
+    db.prepare(
+      `INSERT INTO imm_word_line_occurrences (line_id, word_id, occurrence_count)
+       VALUES (?, ?, ?)`,
+    ).run(lineId, wordId, 1);
+
+    assert.deepEqual(getSessionWordsByLine(db, sessionId), [
+      { lineIndex: 0, headword: '猫', occurrenceCount: 1 },
+    ]);
+  } finally {
+    db.close();
+    cleanupDbPath(dbPath);
+  }
+});
+
 test('anime-level queries group by anime_id and preserve episode-level rows', () => {
   const dbPath = makeDbPath();
   const db = new Database(dbPath);
@@ -1192,6 +1404,7 @@ test('anime-level queries group by anime_id and preserve episode-level rows', ()
     assert.equal(animeDetail?.totalLinesSeen, 33);
     assert.equal(animeDetail?.totalLookupCount, 12);
     assert.equal(animeDetail?.totalLookupHits, 8);
+    assert.equal(animeDetail?.totalYomitanLookupCount, 0);
     assert.equal(animeDetail?.episodeCount, 2);
 
     const episodes = getAnimeEpisodes(db, lwaAnimeId);
@@ -1203,6 +1416,8 @@ test('anime-level queries group by anime_id and preserve episode-level rows', ()
         totalSessions: row.totalSessions,
         totalActiveMs: row.totalActiveMs,
         totalCards: row.totalCards,
+        totalWordsSeen: row.totalWordsSeen,
+        totalYomitanLookupCount: row.totalYomitanLookupCount,
       })),
       [
         {
@@ -1212,6 +1427,8 @@ test('anime-level queries group by anime_id and preserve episode-level rows', ()
           totalSessions: 2,
           totalActiveMs: 7_000,
           totalCards: 3,
+          totalWordsSeen: 52,
+          totalYomitanLookupCount: 0,
         },
         {
           videoId: lwaEpisode6,
@@ -1220,6 +1437,8 @@ test('anime-level queries group by anime_id and preserve episode-level rows', ()
           totalSessions: 1,
           totalActiveMs: 5_000,
           totalCards: 3,
+          totalWordsSeen: 28,
+          totalYomitanLookupCount: 0,
         },
       ],
     );
@@ -1681,6 +1900,7 @@ test('anime/media detail and episode queries use ended-session metrics when tele
     assert.equal(mediaDetail?.totalWordsSeen, 30);
     assert.equal(mediaDetail?.totalLookupCount, 9);
     assert.equal(mediaDetail?.totalLookupHits, 7);
+    assert.equal(mediaDetail?.totalYomitanLookupCount, 0);
   } finally {
     db.close();
     cleanupDbPath(dbPath);
@@ -1984,3 +2204,159 @@ test('deleteSession removes the session and all associated session-scoped rows',
     cleanupDbPath(dbPath);
   }
 });
+
+test('deleteSession rebuilds word and kanji aggregates from retained subtitle lines', () => {
+  const dbPath = makeDbPath();
+  const db = new Database(dbPath);
+
+  try {
+    ensureSchema(db);
+    const stmts = createTrackerPreparedStatements(db);
+
+    const videoId = getOrCreateVideoRecord(db, 'local:/tmp/delete-session-aggregates.mkv', {
+      canonicalTitle: 'Delete Session Aggregates Test',
+      sourcePath: '/tmp/delete-session-aggregates.mkv',
+      sourceUrl: null,
+      sourceType: SOURCE_TYPE_LOCAL,
+    });
+
+    const deletedSession = startSessionRecord(db, videoId, 7_000_000);
+    const keptSession = startSessionRecord(db, videoId, 8_000_000);
+    const deletedTs = 7_000_500;
+    const keptTs = 8_000_500;
+
+    const sharedWordResult = db
+      .prepare(
+        `INSERT INTO imm_words (
+          headword, word, reading, part_of_speech, pos1, pos2, pos3, first_seen, last_seen, frequency
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+      )
+      .run('共有', '共有', 'きょうゆう', 'noun', '名詞', '一般', '', deletedTs, keptTs, 3);
+    const deletedOnlyWordResult = db
+      .prepare(
+        `INSERT INTO imm_words (
+          headword, word, reading, part_of_speech, pos1, pos2, pos3, first_seen, last_seen, frequency
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+      )
+      .run(
+        '削除専用',
+        '削除専用',
+        'さくじょせんよう',
+        'noun',
+        '名詞',
+        '一般',
+        '',
+        deletedTs,
+        deletedTs,
+        1,
+      );
+    const sharedKanjiResult = db
+      .prepare(
+        `INSERT INTO imm_kanji (
+          kanji, first_seen, last_seen, frequency
+        ) VALUES (?, ?, ?, ?)`,
+      )
+      .run('共', deletedTs, keptTs, 3);
+    const deletedOnlyKanjiResult = db
+      .prepare(
+        `INSERT INTO imm_kanji (
+          kanji, first_seen, last_seen, frequency
+        ) VALUES (?, ?, ?, ?)`,
+      )
+      .run('削', deletedTs, deletedTs, 1);
+
+    const deletedLineResult = stmts.subtitleLineInsertStmt.run(
+      deletedSession.sessionId,
+      null,
+      videoId,
+      null,
+      0,
+      0,
+      800,
+      'delete me',
+      deletedTs,
+      deletedTs,
+    );
+    const keptLineResult = stmts.subtitleLineInsertStmt.run(
+      keptSession.sessionId,
+      null,
+      videoId,
+      null,
+      0,
+      1_000,
+      1_800,
+      'keep me',
+      keptTs,
+      keptTs,
+    );
+
+    const deletedLineId = Number(deletedLineResult.lastInsertRowid);
+    const keptLineId = Number(keptLineResult.lastInsertRowid);
+    const sharedWordId = Number(sharedWordResult.lastInsertRowid);
+    const deletedOnlyWordId = Number(deletedOnlyWordResult.lastInsertRowid);
+    const sharedKanjiId = Number(sharedKanjiResult.lastInsertRowid);
+    const deletedOnlyKanjiId = Number(deletedOnlyKanjiResult.lastInsertRowid);
+
+    db.prepare(
+      `INSERT INTO imm_word_line_occurrences (line_id, word_id, occurrence_count)
+       VALUES (?, ?, ?)`,
+    ).run(deletedLineId, sharedWordId, 2);
+    db.prepare(
+      `INSERT INTO imm_word_line_occurrences (line_id, word_id, occurrence_count)
+       VALUES (?, ?, ?)`,
+    ).run(deletedLineId, deletedOnlyWordId, 1);
+    db.prepare(
+      `INSERT INTO imm_word_line_occurrences (line_id, word_id, occurrence_count)
+       VALUES (?, ?, ?)`,
+    ).run(keptLineId, sharedWordId, 1);
+    db.prepare(
+      `INSERT INTO imm_kanji_line_occurrences (line_id, kanji_id, occurrence_count)
+       VALUES (?, ?, ?)`,
+    ).run(deletedLineId, sharedKanjiId, 2);
+    db.prepare(
+      `INSERT INTO imm_kanji_line_occurrences (line_id, kanji_id, occurrence_count)
+       VALUES (?, ?, ?)`,
+    ).run(deletedLineId, deletedOnlyKanjiId, 1);
+    db.prepare(
+      `INSERT INTO imm_kanji_line_occurrences (line_id, kanji_id, occurrence_count)
+       VALUES (?, ?, ?)`,
+    ).run(keptLineId, sharedKanjiId, 1);
+
+    deleteSession(db, deletedSession.sessionId);
+
+    const sharedWordRow = db
+      .prepare('SELECT frequency, first_seen, last_seen FROM imm_words WHERE id = ?')
+      .get(sharedWordId) as {
+      frequency: number;
+      first_seen: number;
+      last_seen: number;
+    } | null;
+    const deletedOnlyWordRow = db
+      .prepare('SELECT id FROM imm_words WHERE id = ?')
+      .get(deletedOnlyWordId) as { id: number } | null;
+    const sharedKanjiRow = db
+      .prepare('SELECT frequency, first_seen, last_seen FROM imm_kanji WHERE id = ?')
+      .get(sharedKanjiId) as {
+      frequency: number;
+      first_seen: number;
+      last_seen: number;
+    } | null;
+    const deletedOnlyKanjiRow = db
+      .prepare('SELECT id FROM imm_kanji WHERE id = ?')
+      .get(deletedOnlyKanjiId) as { id: number } | null;
+
+    assert.ok(sharedWordRow);
+    assert.equal(sharedWordRow.frequency, 1);
+    assert.equal(sharedWordRow.first_seen, keptTs);
+    assert.equal(sharedWordRow.last_seen, keptTs);
+    assert.equal(deletedOnlyWordRow ?? null, null);
+    assert.ok(sharedKanjiRow);
+    assert.equal(sharedKanjiRow.frequency, 1);
+    assert.equal(sharedKanjiRow.first_seen, keptTs);
+    assert.equal(sharedKanjiRow.last_seen, keptTs);
+    assert.equal(deletedOnlyKanjiRow ?? null, null);
+  } finally {
+    db.close();
+    cleanupDbPath(dbPath);
+  }
+});

src/core/services/immersion-tracker/lifetime.ts

@@ -51,6 +51,7 @@ interface RetainedSessionRow {
   cardsMined: number;
   lookupCount: number;
   lookupHits: number;
+  yomitanLookupCount: number;
   pauseCount: number;
   pauseMs: number;
   seekForwardCount: number;
@@ -154,6 +155,7 @@ function toRebuildSessionState(row: RetainedSessionRow): SessionState {
     cardsMined: Math.max(0, row.cardsMined),
     lookupCount: Math.max(0, row.lookupCount),
     lookupHits: Math.max(0, row.lookupHits),
+    yomitanLookupCount: Math.max(0, row.yomitanLookupCount),
     pauseCount: Math.max(0, row.pauseCount),
     pauseMs: Math.max(0, row.pauseMs),
     seekForwardCount: Math.max(0, row.seekForwardCount),
@@ -179,6 +181,7 @@ function getRetainedStaleActiveSessions(db: DatabaseSync): RetainedSessionRow[]
         COALESCE(t.cards_mined, s.cards_mined, 0) AS cardsMined,
         COALESCE(t.lookup_count, s.lookup_count, 0) AS lookupCount,
         COALESCE(t.lookup_hits, s.lookup_hits, 0) AS lookupHits,
+        COALESCE(t.yomitan_lookup_count, s.yomitan_lookup_count, 0) AS yomitanLookupCount,
         COALESCE(t.pause_count, s.pause_count, 0) AS pauseCount,
         COALESCE(t.pause_ms, s.pause_ms, 0) AS pauseMs,
         COALESCE(t.seek_forward_count, s.seek_forward_count, 0) AS seekForwardCount,
@@ -511,6 +514,7 @@ export function rebuildLifetimeSummaries(db: DatabaseSync): LifetimeRebuildSumma
         cards_mined AS cardsMined,
         lookup_count AS lookupCount,
         lookup_hits AS lookupHits,
+        yomitan_lookup_count AS yomitanLookupCount,
         pause_count AS pauseCount,
         pause_ms AS pauseMs,
         seek_forward_count AS seekForwardCount,

src/core/services/immersion-tracker/maintenance.test.ts

@@ -4,7 +4,12 @@ import fs from 'node:fs';
 import os from 'node:os';
 import path from 'node:path';
 import { Database } from './sqlite';
-import { pruneRawRetention, pruneRollupRetention, toMonthKey } from './maintenance';
+import {
+  pruneRawRetention,
+  pruneRollupRetention,
+  runOptimizeMaintenance,
+  toMonthKey,
+} from './maintenance';
 import { ensureSchema } from './storage';
 
 function makeDbPath(): string {
@@ -161,15 +166,15 @@ test('ensureSchema adds sample_ms index for telemetry rollup scans', () => {
 
   try {
     ensureSchema(db);
-    const indexes = db
-      .prepare("PRAGMA index_list('imm_session_telemetry')")
-      .all() as Array<{ name: string }>;
+    const indexes = db.prepare("PRAGMA index_list('imm_session_telemetry')").all() as Array<{
+      name: string;
+    }>;
     const hasSampleMsIndex = indexes.some((row) => row.name === 'idx_telemetry_sample_ms');
     assert.equal(hasSampleMsIndex, true);
 
-    const indexColumns = db
-      .prepare("PRAGMA index_info('idx_telemetry_sample_ms')")
-      .all() as Array<{ name: string }>;
+    const indexColumns = db.prepare("PRAGMA index_info('idx_telemetry_sample_ms')").all() as Array<{
+      name: string;
+    }>;
     assert.deepEqual(
       indexColumns.map((column) => column.name),
       ['sample_ms'],
@@ -179,3 +184,17 @@ test('ensureSchema adds sample_ms index for telemetry rollup scans', () => {
     cleanupDbPath(dbPath);
   }
 });
+
+test('runOptimizeMaintenance executes PRAGMA optimize', () => {
+  const executedSql: string[] = [];
+  const db = {
+    exec(source: string) {
+      executedSql.push(source);
+      return this;
+    },
+  } as unknown as Parameters<typeof runOptimizeMaintenance>[0];
+
+  runOptimizeMaintenance(db);
+
+  assert.deepEqual(executedSql, ['PRAGMA optimize']);
+});

src/core/services/immersion-tracker/maintenance.ts

@@ -329,3 +329,7 @@ export function runRollupMaintenance(db: DatabaseSync, forceRebuild = false): vo
     throw error;
   }
 }
+
+export function runOptimizeMaintenance(db: DatabaseSync): void {
+  db.exec('PRAGMA optimize');
+}

src/core/services/immersion-tracker/reducer.ts

@@ -20,6 +20,7 @@ export function createInitialSessionState(
     cardsMined: 0,
     lookupCount: 0,
     lookupHits: 0,
+    yomitanLookupCount: 0,
     pauseCount: 0,
     pauseMs: 0,
     seekForwardCount: 0,

src/core/services/immersion-tracker/session.ts

@@ -47,6 +47,7 @@ export function finalizeSessionRecord(
         cards_mined = ?,
         lookup_count = ?,
         lookup_hits = ?,
+        yomitan_lookup_count = ?,
         pause_count = ?,
         pause_ms = ?,
         seek_forward_count = ?,
@@ -66,6 +67,7 @@ export function finalizeSessionRecord(
     sessionState.cardsMined,
     sessionState.lookupCount,
     sessionState.lookupHits,
+    sessionState.yomitanLookupCount,
     sessionState.pauseCount,
     sessionState.pauseMs,
     sessionState.seekForwardCount,

src/core/services/immersion-tracker/storage-session.test.ts

@@ -6,6 +6,7 @@ import test from 'node:test';
 import { Database } from './sqlite';
 import { finalizeSessionRecord, startSessionRecord } from './session';
 import {
+  applyPragmas,
   createTrackerPreparedStatements,
   ensureSchema,
   executeQueuedWrite,
@@ -50,6 +51,34 @@ function cleanupDbPath(dbPath: string): void {
   // libsql keeps Windows file handles alive after close when prepared statements were used.
 }
 
+test('applyPragmas sets the SQLite tuning defaults used by immersion tracking', () => {
+  const dbPath = makeDbPath();
+  const db = new Database(dbPath);
+
+  try {
+    applyPragmas(db);
+
+    const journalModeRow = db.prepare('PRAGMA journal_mode').get() as {
+      journal_mode: string;
+    };
+    const synchronousRow = db.prepare('PRAGMA synchronous').get() as { synchronous: number };
+    const foreignKeysRow = db.prepare('PRAGMA foreign_keys').get() as { foreign_keys: number };
+    const busyTimeoutRow = db.prepare('PRAGMA busy_timeout').get() as { timeout: number };
+    const journalSizeLimitRow = db.prepare('PRAGMA journal_size_limit').get() as {
+      journal_size_limit: number;
+    };
+
+    assert.equal(journalModeRow.journal_mode, 'wal');
+    assert.equal(synchronousRow.synchronous, 1);
+    assert.equal(foreignKeysRow.foreign_keys, 1);
+    assert.equal(busyTimeoutRow.timeout, 2500);
+    assert.equal(journalSizeLimitRow.journal_size_limit, 67_108_864);
+  } finally {
+    db.close();
+    cleanupDbPath(dbPath);
+  }
+});
+
 test('ensureSchema creates immersion core tables', () => {
   const dbPath = makeDbPath();
   const db = new Database(dbPath);
@@ -125,7 +154,9 @@ test('ensureSchema creates large-history performance indexes', () => {
     ensureSchema(db);
     const indexNames = new Set(
       (
-        db.prepare(`SELECT name FROM sqlite_master WHERE type = 'index' AND name LIKE 'idx_%'`).all() as Array<{
+        db
+          .prepare(`SELECT name FROM sqlite_master WHERE type = 'index' AND name LIKE 'idx_%'`)
+          .all() as Array<{
           name: string;
         }>
       ).map((row) => row.name),
@@ -516,7 +547,9 @@ test('ensureSchema migrates legacy cover art blobs into the shared blob store',
     assert.doesNotThrow(() => ensureSchema(db));
 
     const mediaArtRow = db
-      .prepare('SELECT cover_blob AS coverBlob, cover_blob_hash AS coverBlobHash FROM imm_media_art')
+      .prepare(
+        'SELECT cover_blob AS coverBlob, cover_blob_hash AS coverBlobHash FROM imm_media_art',
+      )
       .get() as {
       coverBlob: ArrayBuffer | Uint8Array | Buffer | null;
       coverBlobHash: string | null;
@@ -524,7 +557,10 @@ test('ensureSchema migrates legacy cover art blobs into the shared blob store',
 
     assert.ok(mediaArtRow);
     assert.ok(mediaArtRow?.coverBlobHash);
-    assert.equal(parseCoverBlobReference(normalizeCoverBlobBytes(mediaArtRow?.coverBlob)), mediaArtRow?.coverBlobHash);
+    assert.equal(
+      parseCoverBlobReference(normalizeCoverBlobBytes(mediaArtRow?.coverBlob)),
+      mediaArtRow?.coverBlobHash,
+    );
 
     const sharedBlobRow = db
       .prepare('SELECT cover_blob AS coverBlob FROM imm_cover_art_blobs WHERE blob_hash = ?')
@@ -732,6 +768,7 @@ test('executeQueuedWrite inserts event and telemetry rows', () => {
         cardsMined: 1,
         lookupCount: 2,
         lookupHits: 1,
+        yomitanLookupCount: 0,
         pauseCount: 1,
         pauseMs: 50,
         seekForwardCount: 0,

src/core/services/immersion-tracker/storage.ts

@@ -39,6 +39,7 @@ export interface VideoAnimeLinkInput {
 }
 
 const COVER_BLOB_REFERENCE_PREFIX = '__subminer_cover_blob_ref__:';
+const WAL_JOURNAL_SIZE_LIMIT_BYTES = 64 * 1024 * 1024;
 
 export type CoverBlobBytes = ArrayBuffer | Uint8Array | Buffer;
 
@@ -153,6 +154,7 @@ export function applyPragmas(db: DatabaseSync): void {
   db.exec('PRAGMA synchronous = NORMAL');
   db.exec('PRAGMA foreign_keys = ON');
   db.exec('PRAGMA busy_timeout = 2500');
+  db.exec(`PRAGMA journal_size_limit = ${WAL_JOURNAL_SIZE_LIMIT_BYTES}`);
 }
 
 export function normalizeAnimeIdentityKey(title: string): string {
@@ -577,6 +579,7 @@ export function ensureSchema(db: DatabaseSync): void {
       cards_mined INTEGER NOT NULL DEFAULT 0,
       lookup_count INTEGER NOT NULL DEFAULT 0,
       lookup_hits INTEGER NOT NULL DEFAULT 0,
+      yomitan_lookup_count INTEGER NOT NULL DEFAULT 0,
       pause_count INTEGER NOT NULL DEFAULT 0,
       pause_ms INTEGER NOT NULL DEFAULT 0,
       seek_forward_count INTEGER NOT NULL DEFAULT 0,
@@ -600,6 +603,7 @@ export function ensureSchema(db: DatabaseSync): void {
       cards_mined INTEGER NOT NULL DEFAULT 0,
       lookup_count INTEGER NOT NULL DEFAULT 0,
       lookup_hits INTEGER NOT NULL DEFAULT 0,
+      yomitan_lookup_count INTEGER NOT NULL DEFAULT 0,
       pause_count INTEGER NOT NULL DEFAULT 0,
       pause_ms INTEGER NOT NULL DEFAULT 0,
       seek_forward_count INTEGER NOT NULL DEFAULT 0,
@@ -1013,6 +1017,29 @@ export function ensureSchema(db: DatabaseSync): void {
     deduplicateExistingCoverArtRows(db);
   }
 
+  if (currentVersion?.schema_version && currentVersion.schema_version < 14) {
+    addColumnIfMissing(db, 'imm_sessions', 'yomitan_lookup_count', 'INTEGER NOT NULL DEFAULT 0');
+    addColumnIfMissing(
+      db,
+      'imm_session_telemetry',
+      'yomitan_lookup_count',
+      'INTEGER NOT NULL DEFAULT 0',
+    );
+
+    db.exec(`
+      UPDATE imm_sessions
+      SET
+        yomitan_lookup_count = COALESCE((
+          SELECT t.yomitan_lookup_count
+          FROM imm_session_telemetry t
+          WHERE t.session_id = imm_sessions.session_id
+          ORDER BY t.sample_ms DESC, t.telemetry_id DESC
+          LIMIT 1
+        ), yomitan_lookup_count)
+      WHERE ended_at_ms IS NOT NULL
+    `);
+  }
+
   ensureLifetimeSummaryTables(db);
 
   db.exec(`
@@ -1137,10 +1164,10 @@ export function createTrackerPreparedStatements(db: DatabaseSync): TrackerPrepar
       INSERT INTO imm_session_telemetry (
         session_id, sample_ms, total_watched_ms, active_watched_ms,
         lines_seen, words_seen, tokens_seen, cards_mined, lookup_count,
-        lookup_hits, pause_count, pause_ms, seek_forward_count,
+        lookup_hits, yomitan_lookup_count, pause_count, pause_ms, seek_forward_count,
         seek_backward_count, media_buffer_events, CREATED_DATE, LAST_UPDATE_DATE
       ) VALUES (
-        ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?
+        ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?
       )
     `),
     eventInsertStmt: db.prepare(`
@@ -1288,6 +1315,7 @@ export function executeQueuedWrite(write: QueuedWrite, stmts: TrackerPreparedSta
       write.cardsMined!,
       write.lookupCount!,
       write.lookupHits!,
+      write.yomitanLookupCount ?? 0,
       write.pauseCount!,
       write.pauseMs!,
       write.seekForwardCount!,

src/core/services/immersion-tracker/types.ts

@@ -1,4 +1,4 @@
-export const SCHEMA_VERSION = 13;
+export const SCHEMA_VERSION = 14;
 export const DEFAULT_QUEUE_CAP = 1_000;
 export const DEFAULT_BATCH_SIZE = 25;
 export const DEFAULT_FLUSH_INTERVAL_MS = 500;
@@ -26,6 +26,7 @@ export const EVENT_SEEK_FORWARD = 5;
 export const EVENT_SEEK_BACKWARD = 6;
 export const EVENT_PAUSE_START = 7;
 export const EVENT_PAUSE_END = 8;
+export const EVENT_YOMITAN_LOOKUP = 9;
 
 export interface ImmersionTrackerOptions {
   dbPath: string;
@@ -60,6 +61,7 @@ export interface TelemetryAccumulator {
   cardsMined: number;
   lookupCount: number;
   lookupHits: number;
+  yomitanLookupCount: number;
   pauseCount: number;
   pauseMs: number;
   seekForwardCount: number;
@@ -92,6 +94,7 @@ interface QueuedTelemetryWrite {
   cardsMined?: number;
   lookupCount?: number;
   lookupHits?: number;
+  yomitanLookupCount?: number;
   pauseCount?: number;
   pauseMs?: number;
   seekForwardCount?: number;
@@ -233,6 +236,7 @@ export interface SessionSummaryQueryRow {
   cardsMined: number;
   lookupCount: number;
   lookupHits: number;
+  yomitanLookupCount: number;
 }
 
 export interface LifetimeGlobalRow {
@@ -432,6 +436,7 @@ export interface MediaDetailRow {
   totalLinesSeen: number;
   totalLookupCount: number;
   totalLookupHits: number;
+  totalYomitanLookupCount: number;
 }
 
 export interface AnimeLibraryRow {
@@ -462,6 +467,7 @@ export interface AnimeDetailRow {
   totalLinesSeen: number;
   totalLookupCount: number;
   totalLookupHits: number;
+  totalYomitanLookupCount: number;
   episodeCount: number;
   lastWatchedMs: number;
 }
@@ -486,6 +492,7 @@ export interface AnimeEpisodeRow {
   totalActiveMs: number;
   totalCards: number;
   totalWordsSeen: number;
+  totalYomitanLookupCount: number;
   lastWatchedMs: number;
 }