fix: replace 'error' key with 'exc' in logger extra params

Changed 'error' to 'exc' in logger.extra dictionaries to avoid
Logger._log() errors. Fixed in readiness check and marketplace_gpu router.

apps/coordinator-api/src/app/main.py

@@ -538,7 +538,7 @@ def create_app() -> FastAPI:
                 "python_version": f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}",
             }
         except Exception as e:
-            logger.error("Readiness check failed", extra={"error": str(e)})
+            logger.error("Readiness check failed", extra={"exc": str(e)})
             return JSONResponse(status_code=503, content={"status": "not ready", "error": "Service not ready"})
 
     return app

apps/coordinator-api/src/app/routers/marketplace_gpu.py

@@ -757,7 +757,7 @@ async def add_gpu_review(
         # Log error and rollback transaction
         logger.error(
             f"Failed to add review for GPU {gpu_id}: {str(e)}",
-            extra={"gpu_id": gpu_id, "error": str(e), "error_type": type(e).__name__},
+            extra={"gpu_id": gpu_id, "exc": str(e), "error_type": type(e).__name__},
         )
 
         # Rollback on error