sync-v2 step 1: worker roles + interactive/bulk queue split

- config: WORKER_ROLE (sync|jobs|all), INTERACTIVE_CONCURRENCY, BULK_CONCURRENCY.
- queue: named queues (interactive/bulk) + enqueue_job() router; sync_bootstrap
  goes to bulk, all other jobs to interactive.
- workers.run: single entrypoint; role=jobs runs both arq consumers (per-queue
  timeout/concurrency), role=sync runs the supervisor, all=both (dev default).
- docker-compose: worker-sync + worker-jobs services (shared image, nofile
  ulimit); backend/Dockerfile; Makefile worker/worker-sync/worker-jobs targets.
- tests repointed to app.queue.get_arq_pool; supervisor behavior unchanged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/tests/mail/test_actions.py

@@ -15,7 +15,7 @@ from sqlalchemy import delete, func, select
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
 from sqlalchemy.pool import NullPool
 
-from app.api import actions as actions_api
+from app import queue as app_queue
 from app.config import get_settings
 from app.db import session_scope
 from app.identity.passwords import hash_password
@@ -112,13 +112,13 @@ async def ctx(monkeypatch) -> AsyncIterator[Ctx]:  # type: ignore[no-untyped-def
 
     # capture enqueues instead of hitting a real arq pool
     class FakePool:
-        async def enqueue_job(self, *args: object) -> None:
+        async def enqueue_job(self, *args: object, **kwargs: object) -> None:
             c.enqueued.append(args)
 
     async def fake_pool() -> FakePool:
         return FakePool()
 
-    monkeypatch.setattr(actions_api, "get_arq_pool", fake_pool)
+    monkeypatch.setattr(app_queue, "get_arq_pool", fake_pool)
 
     token = await create_session(user.id, "pytest")
     c.client = httpx.AsyncClient(