feat: grouping phase 1 — schema, ungrouped tab, time-window grouping, hash verification

Schema:
- Add GroupingSource enum (ALBUM, MANUAL, AUTO_TIME, AUTO_PATTERN, etc.)
- Add groupingSource field to PackageGroup with backfill
- Add SystemNotification model for persistent alerts
- Add NotificationType and NotificationSeverity enums

Ungrouped staging tab:
- Add listUngroupedPackages/countUngroupedPackages queries
- Add "Ungrouped" tab to STL page showing packages without a group

Time-window auto-grouping:
- After album grouping, cluster ungrouped packages within configurable
  time window (default 5 min, AUTO_GROUP_TIME_WINDOW_MINUTES env var)
- Groups named from common filename prefix
- Groups created with groupingSource=AUTO_TIME

Hash verification after split:
- Re-hash split parts and compare to original contentHash
- Log error and create SystemNotification on mismatch
- Prevents silently corrupted split uploads

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

docs/superpowers/plans/2026-03-30-grouping-phase1-implementation.md

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+# Grouping Phase 1: Foundation + Time-Window Grouping
+
+> **For agentic workers:** Use superpowers:subagent-driven-development to implement this plan.
+
+**Goal:** Add grouping infrastructure (schema, enums, notifications model), an ungrouped staging queue in the UI, and time-window auto-grouping as the first automatic signal beyond album grouping.
+
+**Architecture:** Schema changes lay the foundation. Ungrouped tab is a query filter. Time-window grouping runs as a post-processing pass after album grouping in the worker pipeline.
+
+**Tech Stack:** Prisma schema + migration, worker TypeScript, Next.js App Router.
+
+---
+
+## Task 1: Schema Migration
+
+**Files:**
+- Modify: `prisma/schema.prisma`
+- Create: migration SQL
+
+Add:
+1. `GroupingSource` enum: `ALBUM`, `MANUAL`, `AUTO_TIME`, `AUTO_PATTERN`, `AUTO_REPLY`, `AUTO_ZIP`, `AUTO_CAPTION`
+2. `groupingSource GroupingSource @default(MANUAL)` on `PackageGroup`
+3. `SystemNotification` model with `type`, `severity`, `title`, `message`, `context` (Json), `isRead`
+4. `NotificationType` enum: `HASH_MISMATCH`, `MISSING_PART`, `UPLOAD_FAILED`, `DOWNLOAD_FAILED`, `GROUPING_CONFLICT`, `INTEGRITY_AUDIT`
+5. `NotificationSeverity` enum: `INFO`, `WARNING`, `ERROR`
+
+Backfill: `UPDATE package_groups SET "groupingSource" = 'ALBUM' WHERE "mediaAlbumId" IS NOT NULL`
+
+---
+
+## Task 2: Ungrouped Staging Tab in STL Page
+
+**Files:**
+- Modify: `src/lib/telegram/queries.ts` — add `listUngroupedPackages()` query
+- Modify: `src/app/(app)/stls/page.tsx` — add tab parameter support
+- Modify: `src/app/(app)/stls/_components/stl-table.tsx` — add "Ungrouped" tab
+
+Add a tab next to the existing "Skipped" tab that shows packages where `packageGroupId IS NULL`. Uses the existing `PackageListItem` type and table rendering. This gives users a clear view of files that need manual grouping.
+
+---
+
+## Task 3: Time-Window Auto-Grouping in Worker
+
+**Files:**
+- Create: `worker/src/grouping.ts` — add `processTimeWindowGroups()` after existing `processAlbumGroups()`
+- Modify: `worker/src/worker.ts` — call time-window grouping after album grouping
+- Modify: `worker/src/util/config.ts` — add `autoGroupTimeWindowMinutes` config
+
+After album grouping completes, find remaining ungrouped packages from the same channel scan. Cluster packages whose `sourceMessageId` timestamps are within the configured window (default 5 minutes). Create groups for clusters of 2+ with `groupingSource = AUTO_TIME` and name derived from the common filename prefix or first file's base name.
+
+---
+
+## Task 4: Hash Verification After Split
+
+**Files:**
+- Modify: `worker/src/worker.ts` — add hash re-check after concat+split
+- Modify: `worker/src/archive/hash.ts` — (no changes needed, reuse `hashParts`)
+
+After `concatenateFiles()` + `byteLevelSplit()`, re-hash the split parts and compare to the original `contentHash`. If mismatch, log error and create a `SystemNotification` (once that table exists). This closes the integrity gap identified in the audit.
+
+---
+
+## Task 5: Build & Deploy
+
+Rebuild worker and app images. Deploy. Verify:
+- Worker logs show `maxPartSizeMB` and new `autoGroupTimeWindowMinutes` in config
+- Ungrouped tab visible in STL page
+- Previously-skipped large archives begin processing