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/schema.prisma

@@ -429,10 +429,13 @@ model TelegramChannel {
   createdAt  DateTime    @default(now())
   updatedAt  DateTime    @updatedAt
 
+  autoGroupEnabled Boolean     @default(true)
+
   accountMaps     AccountChannelMap[]
   packages        Package[]
   skippedPackages SkippedPackage[]
   packageGroups   PackageGroup[]
+  groupingRules   GroupingRule[]
 
   @@index([type, isActive])
   @@index([category])
@@ -847,3 +850,18 @@ model SystemNotification {
   @@index([type])
   @@map("system_notifications")
 }
+
+model GroupingRule {
+  id              String          @id @default(cuid())
+  sourceChannelId String
+  pattern         String          // Regex or keyword pattern learned from manual grouping
+  signalType      GroupingSource  // Which grouping signal this rule applies to
+  confidence      Float           @default(1.0)
+  createdAt       DateTime        @default(now())
+  createdByGroupId String?        // The manual group that spawned this rule
+
+  sourceChannel   TelegramChannel @relation(fields: [sourceChannelId], references: [id], onDelete: Cascade)
+
+  @@index([sourceChannelId])
+  @@map("grouping_rules")
+}