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>

prisma/schema.prisma

@@ -39,9 +39,10 @@ model User {
   settings     UserSettings?
   telegramLink TelegramLink?
   kickstarters Kickstarter[]
-  inviteCodes  InviteCode[]   @relation("InviteCreator")
-  usedInvite   InviteCode?    @relation("InviteUser", fields: [usedInviteId], references: [id], onDelete: SetNull)
-  usedInviteId String?
+  inviteCodes    InviteCode[]   @relation("InviteCreator")
+  usedInvite     InviteCode?    @relation("InviteUser", fields: [usedInviteId], references: [id], onDelete: SetNull)
+  usedInviteId   String?
+  manualUploads  ManualUpload[]
 }
 
 model Account {
@@ -865,3 +866,40 @@ model GroupingRule {
   @@index([sourceChannelId])
   @@map("grouping_rules")
 }
+
+enum ManualUploadStatus {
+  PENDING
+  PROCESSING
+  COMPLETED
+  FAILED
+}
+
+model ManualUpload {
+  id              String             @id @default(cuid())
+  status          ManualUploadStatus @default(PENDING)
+  groupName       String?            // Group name if multiple files
+  userId          String
+  errorMessage    String?
+  createdAt       DateTime           @default(now())
+  completedAt     DateTime?
+
+  files           ManualUploadFile[]
+  user            User               @relation(fields: [userId], references: [id])
+
+  @@index([status])
+  @@map("manual_uploads")
+}
+
+model ManualUploadFile {
+  id              String       @id @default(cuid())
+  uploadId        String
+  fileName        String
+  filePath        String       // Path on shared volume
+  fileSize        BigInt
+  packageId       String?      // Set after processing
+
+  upload          ManualUpload @relation(fields: [uploadId], references: [id], onDelete: Cascade)
+
+  @@index([uploadId])
+  @@map("manual_upload_files")
+}