fix(worker): prune TDLib's unbounded local file cache after each run

TDLib keeps a permanent local copy of every file it downloads or
uploads (via inputFileLocal) with no automatic cleanup. Across the two
worker accounts this had grown to ~270GB, filling the host disk to 91%
and triggering a cascading disk-full failure in the bot's TDLib
session on 2026-08-05. Call optimizeStorage after every ingestion run
to clear it; a 5-minute immunity_delay protects files an in-flight
operation might still reference.

worker/src/tdlib/client.ts

@@ -142,3 +142,34 @@ export async function closeTdlibClient(client: Client): Promise<void> {
     log.warn({ err }, "Error closing TDLib client");
   }
 }
+
+/**
+ * Prune TDLib's local file cache (filesDirectory). TDLib keeps a permanent
+ * copy of every file it has ever downloaded or uploaded — via inputFileLocal
+ * uploads in particular — with no automatic cleanup. That cache is redundant
+ * (the content already lives in the source and destination Telegram chats)
+ * and grows unbounded, so it's cleared after every ingestion run. A short
+ * immunity_delay protects files from an in-flight operation that might still
+ * reference them.
+ */
+export async function optimizeTdlibStorage(
+  client: Client,
+  accountId: string
+): Promise<void> {
+  try {
+    const result = (await client.invoke({
+      _: "optimizeStorage",
+      size: 0,
+      ttl: 0,
+      count: 0,
+      immunity_delay: 300,
+      return_deleted_file_statistics: true,
+    })) as { size?: number; count?: number };
+    log.info(
+      { accountId, freedBytes: result.size, freedCount: result.count },
+      "TDLib local file cache pruned"
+    );
+  } catch (err) {
+    log.warn({ err, accountId }, "TDLib storage optimization failed");
+  }
+}

worker/src/worker.ts

@@ -42,7 +42,7 @@ import {
   isTopicFetchEnabled,
 } from "./db/queries.js";
 import type { ActivityUpdate } from "./db/queries.js";
-import { createTdlibClient, closeTdlibClient } from "./tdlib/client.js";
+import { createTdlibClient, closeTdlibClient, optimizeTdlibStorage } from "./tdlib/client.js";
 import {
   getAccountChats,
   joinChatByInviteLink,
@@ -1203,6 +1203,7 @@ export async function runWorkerForAccount(
       accountLog.info({ counters }, "Ingestion run completed");
     } finally {
       await throttled.flush();
+      await optimizeTdlibStorage(client, account.id);
       await closeTdlibClient(client);
     }
   } catch (err) {