fix: align ML service response schemas

apps/ml-service/src/error.rs

@@ -3,7 +3,12 @@ use axum::{
     response::{IntoResponse, Response},
     Json,
 };
-use serde_json::json;
+use serde::Serialize;
+
+#[derive(Debug, Serialize)]
+pub struct ErrorResponse {
+    pub detail: String,
+}
 
 #[derive(Debug)]
 pub enum ServiceError {
@@ -20,7 +25,7 @@ impl IntoResponse for ServiceError {
             ServiceError::PredictionFailed(msg) => (StatusCode::INTERNAL_SERVER_ERROR, msg),
         };
 
-        let body = Json(json!({ "detail": detail }));
+        let body = Json(ErrorResponse { detail });
         (status, body).into_response()
     }
 }

apps/ml-service/src/routes.rs

@@ -17,17 +17,6 @@ pub struct MetadataResponse {
     pub labels: Vec<String>,
 }
 
-#[derive(Debug, Serialize, Deserialize)]
-pub struct PredictionResponse {
-    pub predictions: Vec<PredictionResult>,
-}
-
-#[derive(Debug, Serialize, Deserialize)]
-pub struct PredictionResult {
-    pub label: String,
-    pub confidence: f32,
-}
-
 pub fn health_response(model_loaded: bool) -> HealthResponse {
     HealthResponse {
         status: "ok".to_string(),
@@ -85,24 +74,4 @@ mod tests {
             vec!["Bercak Daun", "Daun Sehat", "Karat Daun", "Hawar Daun"]
         );
     }
-
-    #[test]
-    fn prediction_response_serializes() {
-        let response = PredictionResponse {
-            predictions: vec![
-                PredictionResult {
-                    label: "Bercak Daun".to_string(),
-                    confidence: 0.95,
-                },
-                PredictionResult {
-                    label: "Daun Sehat".to_string(),
-                    confidence: 0.05,
-                },
-            ],
-        };
-
-        let json = serde_json::to_string(&response).expect("failed to serialize");
-        assert!(json.contains("Bercak Daun"));
-        assert!(json.contains("0.95"));
-    }
 }