fix(video-render): F6 ReliableQueue 적용 (F6 part 4)

- worker.py: poll_once + ReliableQueue + startup recovery
- 4 provider (sora/veo/kling/seedance) dispatch table 보존
- Dockerfile: build context=services/, _shared 포함, PYTHONPATH=/app
- docker-compose.yml: video-render build context 갱신

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

services/video-render/worker.py

@@ -1,7 +1,7 @@
-"""Redis BLPOP worker — queue:video-render → job_type 디스패치 → NAS webhook.
+"""Redis ReliableQueue worker — F6 신뢰성 패턴 (BLMOVE + ack/fail + recovery).
 
 queue:paused 가 set이면 대기 (task-watcher가 박재오 활동 감지 시 set).
-Plan-B-Music worker.py 패턴 — string-based dispatch + getattr (테스트 patch 호환).
+string-based dispatch + getattr (테스트 patch 호환).
 """
 from __future__ import annotations
 
@@ -18,6 +18,7 @@ from providers.sora import run_sora_generation
 from providers.veo import run_veo_generation
 from providers.kling import run_kling_generation
 from providers.seedance import run_seedance_generation
+from _shared.reliable_queue import ReliableQueue
 
 logger = logging.getLogger(__name__)
 
@@ -53,25 +54,42 @@ def _dispatch(payload: dict) -> None:
     fn(task_id, params)
 
 
+async def poll_once(queue: ReliableQueue) -> bool:
+    """F6 — 1 cycle: dequeue → _dispatch → ack/fail. Returns True if a job handled."""
+    result = await queue.dequeue(timeout=5)
+    if result is None:
+        return False
+    payload, raw = result
+    try:
+        await asyncio.to_thread(_dispatch, payload)
+    except Exception:
+        logger.exception("dispatch unhandled exception task_id=%s",
+                         payload.get("task_id"))
+        await queue.fail(raw, payload)
+        return True
+    await queue.ack(raw)
+    return True
+
+
 async def worker_loop():
     redis = aioredis.from_url(REDIS_URL, decode_responses=False)
-    logger.info("video-render worker started (queue=%s)", QUEUE_KEY)
+    queue = ReliableQueue(redis, queue_key=QUEUE_KEY)
+    logger.info("video-render worker started worker_id=%s queue=%s",
+                queue.worker_id, QUEUE_KEY)
+    try:
+        recovered = await queue.recover()
+        if recovered:
+            logger.info("recovered %d orphaned items at startup", recovered)
+    except Exception:
+        logger.exception("startup recover failed")
+
     while True:
         try:
             paused = await redis.get(PAUSED_KEY)
             if paused == b"1":
                 await asyncio.sleep(10)
                 continue
-            item = await redis.blpop(QUEUE_KEY, timeout=1)
-            if item is None:
-                continue
-            _, raw = item
-            try:
-                payload = json.loads(raw)
-            except json.JSONDecodeError:
-                logger.error("invalid queue payload: %r", raw[:200])
-                continue
-            await asyncio.to_thread(_dispatch, payload)
+            await poll_once(queue)
         except asyncio.CancelledError:
             logger.info("worker_loop cancelled")
             raise