feat: pattern/creator grouping, notification UI, failure alerts

Pattern grouping (Signal 3):
- Extract YYYY-MM dates, month names, and project prefixes from filenames
- Auto-group packages sharing the same pattern within a channel
- Groups created with groupingSource=AUTO_PATTERN

Creator grouping (Signal 4):
- Auto-group 3+ ungrouped packages from the same creator within a channel
- Runs after pattern grouping as lowest-priority automatic signal

Notification UI:
- Add NotificationBell component to header with unread badge
- Popover panel shows recent notifications with severity icons
- Mark individual or all notifications as read
- Polls every 30 seconds for updates

Failure notifications:
- Upload/download failures now create SystemNotification records
- Visible in the notification bell alongside hash mismatch alerts

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

worker/src/worker.ts

@@ -47,7 +47,7 @@ import { readRarContents } from "./archive/rar-reader.js";
 import { read7zContents } from "./archive/sevenz-reader.js";
 import { byteLevelSplit, concatenateFiles } from "./archive/split.js";
 import { uploadToChannel } from "./upload/channel.js";
-import { processAlbumGroups, processTimeWindowGroups, type IndexedPackageRef } from "./grouping.js";
+import { processAlbumGroups, processTimeWindowGroups, processPatternGroups, processCreatorGroups, type IndexedPackageRef } from "./grouping.js";
 import { db } from "./db/client.js";
 import type { TelegramAccount, TelegramChannel } from "@prisma/client";
 import type { Client } from "tdl";
@@ -777,6 +777,22 @@ async function processArchiveSets(
           partCount: archiveSet.parts.length,
           accountId: ctx.accountId,
         });
+        // Also create a persistent notification
+        await db.systemNotification.create({
+          data: {
+            type: inferSkipReason(errMsg) === "UPLOAD_FAILED" ? "UPLOAD_FAILED" : "DOWNLOAD_FAILED",
+            severity: "WARNING",
+            title: `Failed to process ${archiveSet.parts[0].fileName}`,
+            message: errMsg,
+            context: {
+              fileName: archiveSet.parts[0].fileName,
+              sourceChannelId: ctx.channel.id,
+              sourceMessageId: Number(archiveSet.parts[0].id),
+              channelTitle: ctx.channelTitle,
+              reason: inferSkipReason(errMsg),
+            },
+          },
+        });
       } catch {
         // Best-effort — don't fail the run if skip recording fails
       }
@@ -794,6 +810,12 @@ async function processArchiveSets(
 
     // Time-window grouping for remaining ungrouped packages
     await processTimeWindowGroups(channel.id, indexedPackageRefs);
+
+    // Pattern-based grouping (date patterns, project slugs)
+    await processPatternGroups(channel.id, indexedPackageRefs);
+
+    // Creator-based grouping (3+ files from same creator)
+    await processCreatorGroups(channel.id, indexedPackageRefs);
   }
 
   return maxProcessedId;