fix(vision): #2208 followup E741 l/r rename for ruff

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

@@ -141,11 +141,11 @@ def call_pro_vlm(
             usage.get("completion_tokens", 0),
         )
         text = _strip_code_fence(raw)
-        l, r_pos = text.find("{"), text.rfind("}")
-        if l < 0 or r_pos <= l:
+        lb, r_pos = text.find("{"), text.rfind("}")
+        if lb < 0 or r_pos <= lb:
             logger.warning("[vision.v2] pro 无JSON elapsed=%.1fs head=%s", elapsed, raw[:200])
             return None
-        obj = json.loads(text[l : r_pos + 1])
+        obj = json.loads(text[lb : r_pos + 1])
         if not isinstance(obj, dict):
             return None
         scene = obj.get("scene") or "通用"

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

@@ -153,9 +153,9 @@ def call_fast_json(
             reasoning_tokens,
         )
         text = _strip_code_fence(raw)
-        l, r = text.find("{"), text.rfind("}")
-        if l >= 0 and r > l:
-            text = text[l : r + 1]
+        lb, rb = text.find("{"), text.rfind("}")
+        if lb >= 0 and rb > lb:
+            text = text[lb : rb + 1]
         try:
             obj = json.loads(text)
         except json.JSONDecodeError: