Give the Telegram fixture roots per-process paths

Two concurrent invocations of the backend suite on one checkout raced on
the fixed .tmp fixture directories: the second run's beforeEach wiped
the directory while the first run's test was mid-flight, surfacing as a
spurious ENOENT on bounded-provider.ogg in the Telegram bounding test
(passed in isolation, failed ~once per full-suite run when runs
overlapped). Suffix both roots with the process pid so each suite owns
its fixtures; the after-hook still removes them.

Author: alexeygrigorev

backend/tests/telegram-conversational.test.ts

@@ -44,7 +44,10 @@ import { conversationalRolloutSnapshot } from '../src/conversation/rollout';
 import type { LambdaEvent } from '../src/types';
 
 const NOW = new Date('2026-07-30T12:00:00.000Z');
-const ROOT = path.resolve('..', '.tmp', 'telegram-conversational-tests');
+// The pid suffix keeps concurrent suite invocations of this checkout from
+// racing on one fixture directory: another process's beforeEach wipes ROOT,
+// which surfaced as a spurious ENOENT on the voice fixture mid-test.
+const ROOT = path.resolve('..', '.tmp', `telegram-conversational-tests-${process.pid}`);
 
 function apiEvent(
   method: string,

backend/tests/todo-media-composed.test.ts

@@ -56,7 +56,9 @@ import type { LambdaEvent } from '../src/types';
 const NOW = new Date('2026-07-30T12:00:00.000Z');
 const ACTOR_ID = 'actor-media-composed';
 const CHAT_ID = '9201';
-const ROOT = path.resolve('..', '.tmp', 'todo-media-composed');
+// Pid suffix: see telegram-conversational.test.ts — concurrent suite runs
+// must not share one fixture directory.
+const ROOT = path.resolve('..', '.tmp', `todo-media-composed-${process.pid}`);
 
 function validOgg(): Buffer {
   const body = Buffer.concat([Buffer.from('OpusHead'), Buffer.alloc(11)]);