fix: honor fal scale adjust mask requests

app/api/canvas/local-edit/route.ts

@@ -471,6 +471,16 @@ function resolveScaleAdjustPreferredModelId(params: {
     const maskCapableGptImage2 = gptImage2Candidates
       .filter(isScaleAdjustMaskCapableModel)
       .filter((entry) => entry.model.healthStatus !== "auto_disabled");
+    const requestedMaskCapableGptImage2 = requestedModel
+      ? maskCapableGptImage2.find(
+          (entry) =>
+            entry.model.id === requestedModel.model.id ||
+            entry.model.modelId === requestedModel.model.modelId
+        )
+      : null;
+    if (requestedMaskCapableGptImage2) {
+      return requestedMaskCapableGptImage2.model.id;
+    }
     if (maskCapableGptImage2[0]) {
       return maskCapableGptImage2[0].model.id;
     }
@@ -5410,11 +5420,22 @@ export async function POST(request: NextRequest) {
       } catch (error) {
         scaleAdjustPatchReferenceFailed = true;
         console.warn(
-          "[Canvas Local Edit] Scale adjust patch reference failed; falling back to source-only coordinate prompt:",
+          "[Canvas Local Edit] Scale adjust patch reference failed:",
           {
             error: error instanceof Error ? error.message : String(error),
+            structureLockedPatchWorkflow: useScaleAdjustStructureLockedPatchWorkflow,
           }
         );
+        if (useScaleAdjustStructureLockedPatchWorkflow) {
+          return NextResponse.json(
+            {
+              success: false,
+              error:
+                "比例调整参考图上传失败，请稍后重试；已停止本次生成以避免返回无效结果。",
+            },
+            { status: 503 }
+          );
+        }
       }
     }
     const shouldCreateScaleAdjustCropReferences =