refactor(logging): switch to parameterized logging for improved performance and clarity

- Replaced f-strings with parameterized logging calls across routes, services, and repositories to optimize log message evaluation.
- Improved exception handling by using `logger.exception` where appropriate for automatic traceback logging.

backend/app/main.py

@@ -320,7 +320,7 @@ async def health_check() -> JSONResponse:
             "message": f"Database connection failed: {e!s}",
         }
         response_status = status.HTTP_503_SERVICE_UNAVAILABLE
-        logger.error(f"Health check failed - database error: {e}")
+        logger.error("Health check failed - database error: %s", e)
 
     return JSONResponse(status_code=response_status, content=health_status)