feat: complete remaining features — training, FTS, bot groups, repair, re-tag

Manual override training (GroupingRule):
- Learn patterns from manual group creation (common filename prefix or creator)
- Apply learned rules as first auto-grouping pass (highest confidence after albums)
- GroupingRule model stores pattern, channel, signal type, confidence

Hash verification after upload:
- Re-hash upload files on disk before indexing to catch disk corruption
- Creates HASH_MISMATCH notification on discrepancy

Grouping conflict detection:
- After all grouping passes, check if grouped packages match rules from different groups
- Creates GROUPING_CONFLICT notification for manual review

Per-channel grouping flags:
- Add autoGroupEnabled boolean to TelegramChannel (default true)
- Auto-grouping passes (all except album) gated behind this flag
- Album grouping always runs as it reflects Telegram's native behavior

Full-text search (tsvector):
- Add searchVector tsvector column with GIN index and auto-update trigger
- Backfill 1870 existing packages
- FTS with ts_rank for ranked results, ILIKE fallback for short/failed queries
- Applied to both web app and bot search

Bot group awareness:
- /group <query> — view group info or search groups by name
- /sendgroup <id> — send all packages in a group to linked Telegram account

Bulk repair:
- repairPackageAction clears dest info and resets watermark for re-processing
- Repair button in notification bell for MISSING_PART and HASH_MISMATCH alerts
- /api/notifications/repair endpoint

Retroactive category re-tagging:
- When channel category changes, auto-update tags on all existing packages
- Removes old category tag, adds new one

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

prisma/migrations/20260330140000_grouping_rules_and_flags/migration.sql

@@ -0,0 +1,47 @@
+-- AlterTable: add autoGroupEnabled to telegram_channels
+ALTER TABLE "telegram_channels" ADD COLUMN "autoGroupEnabled" BOOLEAN NOT NULL DEFAULT true;
+
+-- CreateTable: grouping_rules
+CREATE TABLE "grouping_rules" (
+    "id" TEXT NOT NULL,
+    "sourceChannelId" TEXT NOT NULL,
+    "pattern" TEXT NOT NULL,
+    "signalType" "GroupingSource" NOT NULL,
+    "confidence" DOUBLE PRECISION NOT NULL DEFAULT 1.0,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "createdByGroupId" TEXT,
+
+    CONSTRAINT "grouping_rules_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE INDEX "grouping_rules_sourceChannelId_idx" ON "grouping_rules"("sourceChannelId");
+
+-- AddForeignKey
+ALTER TABLE "grouping_rules" ADD CONSTRAINT "grouping_rules_sourceChannelId_fkey" FOREIGN KEY ("sourceChannelId") REFERENCES "telegram_channels"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- Full-text search: add tsvector column and GIN index
+ALTER TABLE "packages" ADD COLUMN IF NOT EXISTS "searchVector" tsvector;
+
+UPDATE "packages" SET "searchVector" = to_tsvector('english',
+  coalesce("fileName", '') || ' ' || coalesce("creator", '') || ' ' || coalesce("sourceCaption", '')
+) WHERE "searchVector" IS NULL;
+
+CREATE INDEX IF NOT EXISTS "packages_search_vector_idx" ON "packages" USING GIN ("searchVector");
+
+-- Trigger to auto-update searchVector on insert/update
+CREATE OR REPLACE FUNCTION packages_search_vector_update() RETURNS trigger AS $$
+BEGIN
+  NEW."searchVector" := to_tsvector('english',
+    coalesce(NEW."fileName", '') || ' ' || coalesce(NEW."creator", '') || ' ' || coalesce(NEW."sourceCaption", '')
+  );
+  RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+DROP TRIGGER IF EXISTS packages_search_vector_trigger ON "packages";
+CREATE TRIGGER packages_search_vector_trigger
+  BEFORE INSERT OR UPDATE OF "fileName", "creator", "sourceCaption"
+  ON "packages"
+  FOR EACH ROW
+  EXECUTE FUNCTION packages_search_vector_update();