feat: enhance error handling with custom HTTP exception responses and middleware improvements

backend/main.py

@@ -70,18 +70,6 @@ async def validation_exception_handler(request: Request, exc: RequestValidationE
     )
 
 
-# Add HTTP exception handler
-@app.exception_handler(HTTPException)
-async def http_exception_handler(request: Request, exc: HTTPException):
-    logger.error(
-        f"HTTP {exc.status_code} for {request.method} {request.url.path}: {exc.detail}"
-    )
-    return JSONResponse(
-        status_code=exc.status_code,
-        content={"detail": exc.detail},
-    )
-
-
 def run_migrations():
     subprocess.run(["alembic", "upgrade", "head"], check=True)