fix: backend improvements (customer health, tests, middleware, corpus)

backend/app/core/middleware.py

@@ -12,6 +12,7 @@ import logging
 import time
 from datetime import datetime
 from typing import Dict, Optional
+from app.core.exceptions import QuotaExceededError
 
 logger = logging.getLogger(__name__)
 
@@ -299,15 +300,17 @@ class QuotaMiddleware(BaseHTTPMiddleware):
         ]
         
         matched_key = None
+        matched_limits = None
         for prefix, limits in quota_map:
             if path.startswith(prefix):
                 matched_key = prefix
+                matched_limits = limits
                 break
         
-        if not matched_key:
+        if not matched_key or matched_limits is None:
             return await call_next(request)
         
-        limit = quota_map[matched_key].get(tier)
+        limit = matched_limits.get(tier)
         if limit is None:
             return await call_next(request)
         
@@ -317,7 +320,6 @@ class QuotaMiddleware(BaseHTTPMiddleware):
             current = await r.incr(key)
             await r.expire(key, 86400)
             if current > limit:
-                from app.core.exceptions import QuotaExceededError
                 raise QuotaExceededError(matched_key)
             request.state.quota_remaining = limit - current
         except QuotaExceededError: