perf(stats): calculate vocabulary totals off main thread

src/core/services/immersion-tracker/vocabulary-summary-worker-runtime.test.ts

@@ -0,0 +1,51 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import test from 'node:test';
+import {
+  resolveVocabularySummaryWorkerPath,
+  VocabularySummaryWorkerRuntime,
+} from './vocabulary-summary-worker-runtime';
+import { Database } from './sqlite';
+import { applyPragmas, ensureSchema } from './storage';
+
+test('vocabulary summary worker reads the database from a separate connection', async () => {
+  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-vocabulary-summary-worker-'));
+  const dbPath = path.join(tempDir, 'immersion.sqlite');
+  const runtime = new VocabularySummaryWorkerRuntime();
+  const db = new Database(dbPath);
+
+  try {
+    applyPragmas(db);
+    ensureSchema(db);
+    db.prepare(
+      `
+      INSERT INTO imm_words (
+        headword, word, reading, part_of_speech, pos1, pos2, pos3,
+        first_seen, last_seen, frequency
+      ) VALUES ('猫', '猫', 'ねこ', 'noun', '名詞', '一般', '', 1, 1, 1)
+    `,
+    ).run();
+    db.close();
+
+    const summary = await runtime.run(dbPath, new Set(['猫']));
+
+    assert.equal(summary.uniqueWords, 1);
+    assert.equal(summary.knownWordCount, 1);
+  } finally {
+    runtime.destroy();
+    try {
+      db.close();
+    } catch {
+      // The worker needs the setup connection closed before it starts.
+    }
+    fs.rmSync(tempDir, { recursive: true, force: true });
+  }
+});
+
+test('vocabulary summary worker module resolves in the current layout', () => {
+  const workerPath = resolveVocabularySummaryWorkerPath();
+  assert.ok(workerPath, 'expected the vocabulary summary worker module to resolve');
+  assert.ok(workerPath.endsWith(__filename.endsWith('.ts') ? '.ts' : '.js'));
+});