feat: file upload from UI, notification dismiss, audit false positive fix

Manual file upload:
- Upload dialog in STL page with drag-and-drop file picker
- Files saved to shared Docker volume (/data/uploads)
- Worker processes via pg_notify('manual_upload') channel
- Hashes, reads metadata, splits >2GB, uploads to Telegram
- Multiple files automatically grouped
- Status polling shows upload/processing/complete states

Notification fixes:
- Add dismiss (X) button on each notification
- Add "Clear" button to remove all notifications
- Fix false positive MISSING_PART alerts from legacy packages
  (only flag when >1 destMessageIds stored but count wrong,
  not when only 1 ID from backfill)

Infrastructure:
- ManualUpload + ManualUploadFile schema + migration
- Shared manual_uploads Docker volume between app and worker
- Upload API routes (POST /api/uploads, GET /api/uploads/[id])
- Worker manual-upload processor with full pipeline

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -28,6 +28,8 @@ services:
       timeout: 5s
       retries: 3
       start_period: 60s
+    volumes:
+      - manual_uploads:/data/uploads
     restart: unless-stopped
     deploy:
       resources:
@@ -54,6 +56,7 @@ services:
     volumes:
       - tdlib_state:/data/tdlib
       - tmp_zips:/tmp/zips
+      - manual_uploads:/data/uploads
     depends_on:
       db:
         condition: service_healthy
@@ -121,6 +124,7 @@ volumes:
   tdlib_state:
   tdlib_bot_state:
   tmp_zips:
+  manual_uploads:
 
 networks:
   frontend: