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/migrations/20260330150000_manual_uploads/migration.sql

@@ -0,0 +1,30 @@
+-- CreateEnum
+CREATE TYPE "ManualUploadStatus" AS ENUM ('PENDING', 'PROCESSING', 'COMPLETED', 'FAILED');
+
+-- CreateTable
+CREATE TABLE "manual_uploads" (
+    "id" TEXT NOT NULL,
+    "status" "ManualUploadStatus" NOT NULL DEFAULT 'PENDING',
+    "groupName" TEXT,
+    "userId" TEXT NOT NULL,
+    "errorMessage" TEXT,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "completedAt" TIMESTAMP(3),
+    CONSTRAINT "manual_uploads_pkey" PRIMARY KEY ("id")
+);
+
+CREATE TABLE "manual_upload_files" (
+    "id" TEXT NOT NULL,
+    "uploadId" TEXT NOT NULL,
+    "fileName" TEXT NOT NULL,
+    "filePath" TEXT NOT NULL,
+    "fileSize" BIGINT NOT NULL,
+    "packageId" TEXT,
+    CONSTRAINT "manual_upload_files_pkey" PRIMARY KEY ("id")
+);
+
+CREATE INDEX "manual_uploads_status_idx" ON "manual_uploads"("status");
+CREATE INDEX "manual_upload_files_uploadId_idx" ON "manual_upload_files"("uploadId");
+
+ALTER TABLE "manual_uploads" ADD CONSTRAINT "manual_uploads_userId_fkey" FOREIGN KEY ("userId") REFERENCES "users"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
+ALTER TABLE "manual_upload_files" ADD CONSTRAINT "manual_upload_files_uploadId_fkey" FOREIGN KEY ("uploadId") REFERENCES "manual_uploads"("id") ON DELETE CASCADE ON UPDATE CASCADE;