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>

src/app/api/notifications/read/route.ts

@@ -3,6 +3,8 @@ import { auth } from "@/lib/auth";
 import {
   markNotificationRead,
   markAllNotificationsRead,
+  dismissNotification,
+  clearAllNotifications,
 } from "@/data/notification.queries";
 
 export const dynamic = "force-dynamic";
@@ -15,8 +17,13 @@ export async function POST(request: Request) {
 
   const body = await request.json().catch(() => ({}));
   const id = body.id as string | undefined;
+  const action = (body.action as string) ?? "read";
 
-  if (id) {
+  if (action === "dismiss" && id) {
+    await dismissNotification(id);
+  } else if (action === "clear") {
+    await clearAllNotifications();
+  } else if (id) {
     await markNotificationRead(id);
   } else {
     await markAllNotificationsRead();