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>

src/app/(app)/stls/page.tsx

@@ -1,6 +1,6 @@
 import { auth } from "@/lib/auth";
 import { redirect } from "next/navigation";
-import { listDisplayItems, searchPackages, getIngestionStatus, getAllPackageTags, listSkippedPackages, countSkippedPackages } from "@/lib/telegram/queries";
+import { listDisplayItems, searchPackages, getIngestionStatus, getAllPackageTags, listSkippedPackages, countSkippedPackages, listUngroupedPackages, countUngroupedPackages } from "@/lib/telegram/queries";
 import { StlTable } from "./_components/stl-table";
 import type { DisplayItem, PackageListItem } from "@/lib/telegram/types";
 
@@ -24,7 +24,7 @@ export default async function StlFilesPage({ searchParams }: Props) {
   const tab = (params.tab as string) ?? "packages";
 
   // Fetch packages, ingestion status, tags, and skipped count in parallel
-  const [result, ingestionStatus, availableTags, skippedCount] = await Promise.all([
+  const [result, ingestionStatus, availableTags, skippedCount, ungroupedCount] = await Promise.all([
     search
       ? searchPackages({
           query: search,
@@ -43,6 +43,7 @@ export default async function StlFilesPage({ searchParams }: Props) {
     getIngestionStatus(),
     getAllPackageTags(),
     countSkippedPackages(),
+    countUngroupedPackages(),
   ]);
 
   // For search results, wrap as DisplayItem[]; for non-search, already DisplayItem[]
@@ -55,6 +56,11 @@ export default async function StlFilesPage({ searchParams }: Props) {
     ? await listSkippedPackages({ page, limit: perPage })
     : null;
 
+  // Fetch ungrouped packages only if on that tab
+  const ungroupedResult = tab === "ungrouped"
+    ? await listUngroupedPackages({ page, limit: perPage })
+    : null;
+
   return (
     <StlTable
       data={displayItems}
@@ -66,6 +72,9 @@ export default async function StlFilesPage({ searchParams }: Props) {
       skippedData={skippedResult?.items ?? []}
       skippedPageCount={skippedResult?.pagination.totalPages ?? 0}
       skippedTotalCount={skippedCount}
+      ungroupedData={ungroupedResult?.items ?? []}
+      ungroupedPageCount={ungroupedResult?.pagination.totalPages ?? 0}
+      ungroupedTotalCount={ungroupedCount}
     />
   );
 }