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/app/queue.py

@@ -1,14 +1,33 @@
-"""arq queue helpers (enqueue side, used by the API)."""
+"""arq queue helpers (enqueue side, used by the API).
+
+Two named queues (refactor §6): ``interactive`` (fast user actions) and ``bulk``
+(backfills). Enqueue via :func:`enqueue_job`, which routes each job to its queue —
+the API never needs to know queue names.
+"""
 
 from __future__ import annotations
 
+from typing import Any
+
 from arq import create_pool
 from arq.connections import ArqRedis, RedisSettings
+from arq.jobs import Job
 
 from app.config import get_settings
 
 _pool: ArqRedis | None = None
 
+QUEUE_INTERACTIVE = "interactive"
+QUEUE_BULK = "bulk"
+
+# Jobs default to the interactive queue; only bulk backfills go to the bulk queue.
+_BULK_JOBS = frozenset({"sync_bootstrap_account"})
+
+
+def queue_for(job_name: str) -> str:
+    """Return the queue a job should run on."""
+    return QUEUE_BULK if job_name in _BULK_JOBS else QUEUE_INTERACTIVE
+
 
 def redis_settings() -> RedisSettings:
     """Return arq RedisSettings derived from ``REDIS_URL``."""
@@ -23,6 +42,13 @@ async def get_arq_pool() -> ArqRedis:
     return _pool
 
 
+async def enqueue_job(name: str, *args: Any, **kwargs: Any) -> Job | None:
+    """Enqueue ``name`` onto its routed queue (interactive/bulk)."""
+    pool = await get_arq_pool()
+    kwargs.setdefault("_queue_name", queue_for(name))
+    return await pool.enqueue_job(name, *args, **kwargs)
+
+
 async def close_arq_pool() -> None:
     """Close the arq pool."""
     global _pool