Fix worker getting stuck during sync: add timeouts, stuck detection, and safety limits

- Add invokeWithTimeout wrapper for TDLib API calls (2min timeout per call)
- Add stuck detection to getChannelMessages: break if from_message_id doesn't advance
- Add stuck detection to getTopicMessages: same protection for topic scanning
- Add stuck detection to getForumTopicList: break if pagination offsets don't advance
- Add max page limit (5000) to all scanning loops to prevent infinite pagination
- Add mutex wait timeout (30min) to prevent indefinite blocking when holder hangs
- Add cycle timeout (4h default, configurable via WORKER_CYCLE_TIMEOUT_MINUTES)
- Fix end-of-page detection to use actual limit value instead of hardcoded 100

Co-authored-by: xCyanGrizzly <53275238+xCyanGrizzly@users.noreply.github.com>

worker/dist/tdlib/topics.d.ts

@@ -0,0 +1,32 @@
+import type { Client } from "tdl";
+import type { ChannelScanResult, ScanProgressCallback } from "./download.js";
+export interface ForumTopic {
+    topicId: bigint;
+    name: string;
+}
+/**
+ * Check if a chat is a forum supergroup (topics enabled).
+ */
+export declare function isChatForum(client: Client, chatId: bigint): Promise<boolean>;
+/**
+ * Get all forum topics in a supergroup.
+ * Includes stuck detection and timeout protection on API calls.
+ */
+export declare function getForumTopicList(client: Client, chatId: bigint): Promise<ForumTopic[]>;
+/**
+ * Fetch messages from a specific forum topic (thread), stopping once
+ * we've scanned past the last-processed boundary (with one page of lookback).
+ * Uses searchChatMessages with message_thread_id to scan within a topic.
+ *
+ * Returns messages in chronological order (oldest first).
+ *
+ * When `lastProcessedMessageId` is null (first run), scans everything.
+ * The worker applies a post-grouping filter to skip fully-processed sets,
+ * and keeps `packageExistsBySourceMessage` as a safety net.
+ *
+ * Safety features:
+ *  - Max page limit to prevent infinite loops
+ *  - Stuck detection: breaks if from_message_id stops advancing
+ *  - Timeout on each TDLib API call
+ */
+export declare function getTopicMessages(client: Client, chatId: bigint, topicId: bigint, lastProcessedMessageId?: bigint | null, limit?: number, onProgress?: ScanProgressCallback): Promise<ChannelScanResult>;