feat: show mining frame toast on OSD and speed up stats session deletes

- Flash mined-frame screenshot as in-overlay image toast for OSD card notifications
- Batch cover art from stored DB blobs via POST /api/stats/covers (no extra AniList fetches)
- Show delete progress toast on stats home and sessions pages
- Refresh only affected rollups on session delete instead of full rebuild
- Rebuild lifetime summaries with aggregate SQL CTEs instead of per-session loop

src/anki-integration.ts

@@ -148,6 +148,7 @@ export class AnkiIntegration {
   private runtime: AnkiIntegrationRuntime;
   private aiConfig: AiConfig;
   private recordCardsMinedCallback: ((count: number, noteIds?: number[]) => void) | null = null;
+  private miningImageOverlayCallback: ((image: string) => void) | null = null;
   private knownWordCacheUpdatedCallback: (() => void) | null = null;
   private consumeSubtitleMiningContextCallback: (() => SubtitleMiningContext | null) | null = null;
   private noteIdRedirects = new Map<number, number>();
@@ -1018,40 +1019,54 @@ export class AnkiIntegration {
       : `Updated card: ${label}`;
 
     const type = this.config.behavior?.notificationType || 'osd';
+    const wantsOsd = type === 'osd' || type === 'both';
+    const wantsSystem =
+      (type === 'system' || type === 'both') && this.notificationCallback !== null;
+    const wantsOverlayImage = wantsOsd && this.miningImageOverlayCallback !== null;
 
-    if (type === 'osd' || type === 'both') {
+    if (wantsOsd) {
       this.showUpdateResult(message, errorSuffix === undefined);
     } else {
       this.clearUpdateProgress();
     }
 
-    if ((type === 'system' || type === 'both') && this.notificationCallback) {
-      let notificationIconPath: string | undefined;
+    if (!wantsSystem && !wantsOverlayImage) {
+      return;
+    }
 
-      if (this.mpvClient && this.mpvClient.currentVideoPath) {
-        try {
-          const timestamp = this.mpvClient.currentTimePos || 0;
-          const notificationIconSource = await resolveMediaGenerationInputPath(
-            this.mpvClient,
-            'video',
-          );
-          if (!notificationIconSource) {
-            throw new Error('No media source available for notification icon');
-          }
-          const iconBuffer = await this.mediaGenerator.generateNotificationIcon(
-            notificationIconSource,
-            timestamp,
-          );
-          if (iconBuffer && iconBuffer.length > 0) {
-            notificationIconPath = this.mediaGenerator.writeNotificationIconToFile(
-              iconBuffer,
-              noteId,
-            );
-          }
-        } catch (err) {
-          log.warn('Failed to generate notification icon:', (err as Error).message);
+    // Generate the frame screenshot once and reuse it for the system notification
+    // icon and the in-overlay image toast.
+    let iconBuffer: Buffer | undefined;
+    if (this.mpvClient && this.mpvClient.currentVideoPath) {
+      try {
+        const timestamp = this.mpvClient.currentTimePos || 0;
+        const notificationIconSource = await resolveMediaGenerationInputPath(
+          this.mpvClient,
+          'video',
+        );
+        if (!notificationIconSource) {
+          throw new Error('No media source available for notification icon');
         }
+        const buffer = await this.mediaGenerator.generateNotificationIcon(
+          notificationIconSource,
+          timestamp,
+        );
+        if (buffer && buffer.length > 0) {
+          iconBuffer = buffer;
+        }
+      } catch (err) {
+        log.warn('Failed to generate notification icon:', (err as Error).message);
       }
+    }
+
+    if (wantsOverlayImage && iconBuffer && this.miningImageOverlayCallback) {
+      this.miningImageOverlayCallback(`data:image/png;base64,${iconBuffer.toString('base64')}`);
+    }
+
+    if (wantsSystem && this.notificationCallback) {
+      const notificationIconPath = iconBuffer
+        ? this.mediaGenerator.writeNotificationIconToFile(iconBuffer, noteId)
+        : undefined;
 
       this.notificationCallback('Anki Card Updated', {
         body: message,
@@ -1364,6 +1379,10 @@ export class AnkiIntegration {
     this.knownWordCacheUpdatedCallback = callback;
   }
 
+  setMiningImageOverlayCallback(callback: ((image: string) => void) | null): void {
+    this.miningImageOverlayCallback = callback;
+  }
+
   setSubtitleMiningContextConsumer(callback: (() => SubtitleMiningContext | null) | null): void {
     this.consumeSubtitleMiningContextCallback = callback;
   }