fix(vision): #2203 V2快速路径两个P0 bug修复

E2E发现两个P0 bug：
1. as_completed(timeout=...)抛TimeoutError时未被捕获，异常直接冒泡到外层，
   跳过了pro VLM兜底路径，导致3/3返回空结果。
   修复：包裹try/except TimeoutError，cancel未完成futures，继续走pro兜底。

2. 外层_step_image_analysis设置client.max_retries=0不生效（ThreadPool线程
   里可能被其他任务覆盖/共享单例状态），实际仍重试1次（2次调用×6s=12s超时）。
   修复：在vlm_fast_json/vlm_fallback内部强制max_retries=0并在finally里恢复。

3. 收紧超时：fast总超时8→6s、lite JSON 6→5s、OCR 8→5s，让lite不够快时
   尽快走pro兜底（pro单次45s足够）。

本地mock验证：fast命中1.5s返回有效portrait_prompt；fast超时6s正确触发pro fallback。

apps/worker/worker_app/tasks/vision/fast_path.py

@@ -21,9 +21,9 @@ logger = logging.getLogger(__name__)
 
 # 可通过环境变量调参（有默认值，无需配置即可跑）
 _IMG_WORKERS = int(os.environ.get("VISION_V2_IMG_WORKERS", "8"))
-_FAST_TIMEOUT = float(os.environ.get("VISION_V2_FAST_TIMEOUT", "8"))
-_FAST_JSON_TIMEOUT = float(os.environ.get("VISION_V2_FAST_JSON_TIMEOUT", "6"))
-_OCR_TIMEOUT = float(os.environ.get("VISION_V2_OCR_TIMEOUT", "6"))
+_FAST_TIMEOUT = float(os.environ.get("VISION_V2_FAST_TIMEOUT", "6"))
+_FAST_JSON_TIMEOUT = float(os.environ.get("VISION_V2_FAST_JSON_TIMEOUT", "5"))
+_OCR_TIMEOUT = float(os.environ.get("VISION_V2_OCR_TIMEOUT", "5"))
 _PRO_TIMEOUT = float(os.environ.get("VISION_V2_PRO_TIMEOUT", "45"))
 
 _FALLBACK_RESULT = {
@@ -62,16 +62,23 @@ def analyze_image_v2(idx: int, img_url: str) -> dict[str, Any]:
     with ThreadPoolExecutor(max_workers=2) as pool:
         f_fj = pool.submit(vlm_fast_json.call_fast_json, img_url, timeout=_FAST_JSON_TIMEOUT)
         f_ocr = pool.submit(ocr_volc.call_ocr, img_url, timeout=_OCR_TIMEOUT)
-        for fut in as_completed([f_fj, f_ocr], timeout=_FAST_TIMEOUT + 2):
-            try:
-                res = fut.result(timeout=1)
-            except Exception as e:
-                logger.warning("[vision.v2] 图片 #%d 子任务异常: %s", idx, e)
-                continue
-            if fut is f_fj and isinstance(res, dict):
-                fj_result = res
-            elif fut is f_ocr and isinstance(res, list):
-                ocr_result = res
+        try:
+            for fut in as_completed([f_fj, f_ocr], timeout=_FAST_TIMEOUT):
+                try:
+                    res = fut.result(timeout=1)
+                except Exception as e:
+                    logger.warning("[vision.v2] 图片 #%d 子任务异常: %s", idx, e)
+                    continue
+                if fut is f_fj and isinstance(res, dict):
+                    fj_result = res
+                elif fut is f_ocr and isinstance(res, list):
+                    ocr_result = res
+        except TimeoutError:
+            # fast 整体超时，取消还没跑完的子任务，继续走 pro 兜底
+            for f in (f_fj, f_ocr):
+                if not f.done():
+                    f.cancel()
+            logger.warning("[vision.v2] 图片 #%d fast路径超时(%.0fs)，走pro兜底", idx, _FAST_TIMEOUT)
 
     fast_elapsed = time.time() - t0
 

apps/worker/worker_app/tasks/vision/vlm_fallback.py

@@ -164,6 +164,8 @@ def call_pro_vlm(
         return None
 
     use_model = model or DEFAULT_PRO_MODEL
+    _orig_retries = client.max_retries
+    client.max_retries = 0
     try:
         raw = client.vision_completion(
             messages=[{"role": "system", "content": system}, {"role": "user", "content": user}],
@@ -175,7 +177,9 @@ def call_pro_vlm(
         )
     except Exception as e:
         logger.warning("[vision.vlm] 图片 #%d pro VLM 调用失败 elapsed=%.1fs err=%s", idx, time.time() - t0, e)
+        client.max_retries = _orig_retries
         return None
+    client.max_retries = _orig_retries
 
     elapsed = time.time() - t0
     if not raw:

apps/worker/worker_app/tasks/vision/vlm_fast_json.py

@@ -93,17 +93,23 @@ def call_fast_json(
             return None
 
         use_model = model or DEFAULT_LITE_MODEL
-        raw = client.vision_completion(
-            messages=[
-                {"role": "system", "content": _FAST_SYSTEM},
-                {"role": "user", "content": _FAST_USER},
-            ],
-            images=[img_url],
-            temperature=0.1,
-            max_tokens=max_tokens,
-            timeout=timeout,
-            model=use_model,
-        )
+        # 强制不重试：lite 是快速路径，失败直接走外层 pro 兜底
+        _orig_retries = client.max_retries
+        client.max_retries = 0
+        try:
+            raw = client.vision_completion(
+                messages=[
+                    {"role": "system", "content": _FAST_SYSTEM},
+                    {"role": "user", "content": _FAST_USER},
+                ],
+                images=[img_url],
+                temperature=0.1,
+                max_tokens=max_tokens,
+                timeout=timeout,
+                model=use_model,
+            )
+        finally:
+            client.max_retries = _orig_retries
         elapsed = time.time() - t0
         if raw is None:
             logger.warning("[vision.v2] fast_json 返回 None elapsed=%.1fs model=%s", elapsed, use_model)