feat: add Telegram integration with forum topic support and creator tracking

Adds full Telegram ZIP ingestion pipeline: TDLib worker service scans source
channels for archive files, deduplicates by content hash, extracts metadata,
uploads to archive channel, and indexes in Postgres. Forum supergroups are
scanned per-topic with topic names used as creator. Filename-based creator
extraction (e.g. "Mammoth Factory - 2026-01.zip") serves as fallback.

Includes admin UI for managing accounts/channels, simplified account setup
(API credentials via env vars), auth code/password submission dialog,
package browser with creator column, and live ingestion activity tracking.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

worker/src/db/locks.ts

@@ -0,0 +1,56 @@
+import { pool } from "./client.js";
+import { childLogger } from "../util/logger.js";
+
+const log = childLogger("locks");
+
+/**
+ * Derive a stable 32-bit integer lock ID from an account ID string.
+ * PostgreSQL advisory locks use bigint, but we use 32-bit for safety.
+ */
+function hashToLockId(accountId: string): number {
+  let hash = 0;
+  for (let i = 0; i < accountId.length; i++) {
+    const char = accountId.charCodeAt(i);
+    hash = (hash << 5) - hash + char;
+    hash |= 0; // Convert to 32-bit integer
+  }
+  return Math.abs(hash);
+}
+
+/**
+ * Try to acquire a PostgreSQL advisory lock for an account.
+ * Returns true if acquired, false if already held by another session.
+ */
+export async function tryAcquireLock(accountId: string): Promise<boolean> {
+  const lockId = hashToLockId(accountId);
+  const client = await pool.connect();
+  try {
+    const result = await client.query<{ pg_try_advisory_lock: boolean }>(
+      "SELECT pg_try_advisory_lock($1)",
+      [lockId]
+    );
+    const acquired = result.rows[0]?.pg_try_advisory_lock ?? false;
+    if (acquired) {
+      log.debug({ accountId, lockId }, "Advisory lock acquired");
+    } else {
+      log.debug({ accountId, lockId }, "Advisory lock already held");
+    }
+    return acquired;
+  } finally {
+    client.release();
+  }
+}
+
+/**
+ * Release the advisory lock for an account.
+ */
+export async function releaseLock(accountId: string): Promise<void> {
+  const lockId = hashToLockId(accountId);
+  const client = await pool.connect();
+  try {
+    await client.query("SELECT pg_advisory_unlock($1)", [lockId]);
+    log.debug({ accountId, lockId }, "Advisory lock released");
+  } finally {
+    client.release();
+  }
+}