fix: Resolve Ruff E402 warnings and clean up imports across multiple modules

monitoring/__init__.py

@@ -3,7 +3,7 @@ from __future__ import annotations
 from datetime import datetime, timedelta
 from typing import Optional
 
-from fastapi import APIRouter, Depends, HTTPException, Query, Response
+from fastapi import APIRouter, Depends, Query, Response
 from prometheus_client import CONTENT_TYPE_LATEST, generate_latest
 from sqlalchemy.orm import Session
 
@@ -94,8 +94,9 @@ async def detailed_health(db: Session = Depends(get_db)) -> dict:
         for m in request_metrics:
             if m.duration_seconds is not None:
                 durations.append(m.duration_seconds)
-            if m.status_code is not None and m.status_code >= 400:
-                error_count += 1
+            if m.status_code is not None:
+                if m.status_code >= 400:
+                    error_count += 1
         total_requests = len(request_metrics)
 
         avg_duration = sum(durations) / len(durations) if durations else 0