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/workers/run.py

@@ -0,0 +1,111 @@
+"""Worker entrypoint (refactor §1).
+
+One image, two roles selected by ``WORKER_ROLE``:
+
+- ``jobs`` — arq consumer for the ``interactive`` and ``bulk`` queues (both in one
+  process, per-queue concurrency/timeout).
+- ``sync`` — runs the account-sync supervisor (long-lived per-account loops).
+- ``all``  — both, for single-process development (the default).
+
+Run with: ``python -m workers.run``.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import logging
+import signal
+from typing import Any
+
+from arq.worker import Worker
+
+from app.config import get_settings
+from app.queue import QUEUE_BULK, QUEUE_INTERACTIVE, redis_settings
+from workers.worker import (
+    BULK_FUNCTIONS,
+    INTERACTIVE_FUNCTIONS,
+    sync_on_shutdown,
+    sync_on_startup,
+)
+
+logger = logging.getLogger(__name__)
+
+# arq requires a non-empty function set; the sync worker consumes a queue nothing
+# is ever enqueued to, so it just keeps the event loop alive for the supervisor.
+_SYNC_CONTROL_QUEUE = "sync:control"
+
+
+async def _noop(ctx: dict[str, Any]) -> None:
+    return None
+
+
+def _worker(
+    functions: list[Any],
+    queue_name: str,
+    max_jobs: int,
+    job_timeout: int,
+    on_startup: Any = None,
+    on_shutdown: Any = None,
+) -> Worker:
+    return Worker(
+        functions=functions,
+        queue_name=queue_name,
+        redis_settings=redis_settings(),
+        max_jobs=max_jobs,
+        job_timeout=job_timeout,
+        on_startup=on_startup,
+        on_shutdown=on_shutdown,
+        handle_signals=False,  # the runner owns signal handling (graceful shutdown)
+    )
+
+
+def build_workers(role: str) -> list[Worker]:
+    """Construct the arq Worker instances for the given role."""
+    s = get_settings()
+    workers: list[Worker] = []
+    if role in ("sync", "all"):
+        workers.append(
+            _worker([_noop], _SYNC_CONTROL_QUEUE, 1, 3600, sync_on_startup, sync_on_shutdown)
+        )
+    if role in ("jobs", "all"):
+        workers.append(
+            _worker(INTERACTIVE_FUNCTIONS, QUEUE_INTERACTIVE, s.interactive_concurrency, 120)
+        )
+        workers.append(_worker(BULK_FUNCTIONS, QUEUE_BULK, s.bulk_concurrency, 3600))
+    return workers
+
+
+async def _run() -> None:
+    logging.basicConfig(level=get_settings().log_level)
+    role = get_settings().worker_role
+    workers = build_workers(role)
+    logger.info("worker starting: role=%s (%d arq worker(s))", role, len(workers))
+
+    tasks = [asyncio.create_task(w.async_run()) for w in workers]
+    stop = asyncio.Event()
+    loop = asyncio.get_running_loop()
+    for sig in (signal.SIGINT, signal.SIGTERM):
+        loop.add_signal_handler(sig, stop.set)
+
+    await stop.wait()
+    logger.info("worker stopping: cancelling %d worker(s)", len(tasks))
+    for task in tasks:
+        task.cancel()  # arq runs each worker's on_shutdown in its finally
+    await asyncio.gather(*tasks, return_exceptions=True)
+
+    from app.db import dispose_engine
+    from app.queue import close_arq_pool
+    from app.redis_client import close_redis
+
+    await dispose_engine()
+    await close_redis()
+    await close_arq_pool()
+    logger.info("worker stopped")
+
+
+def main() -> None:
+    asyncio.run(_run())
+
+
+if __name__ == "__main__":
+    main()