修复重复生成占位的对账判定

收集项目快照中全部同 ID 的生成占位原始记录。

通用队列链在任一重复占位未收口时执行第二次项目读取。

完美像素遇到重复操作占位时失败关闭为冲突。

补充两条缺陷定向测试并同步技术方案与决策记录。

src/components/image-editor/useImageCanvasGenerationWorkflow.test.tsx

@@ -1254,6 +1254,34 @@ describe('useImageCanvasGenerationWorkflow', () => {
     ).toMatchObject({ kind: 'pending', project });
   });
 
+  it('rejects duplicate perfect-pixel dialog ids even when the first record appears applied', () => {
+    const operationId = 'perfect-pixel-duplicate-dialog';
+    const project = createPerfectPixelProject(operationId, 'applied');
+    project.layers.push({
+      itemType: 'generation-dialog',
+      layerId: `generation-dialog:${operationId}:duplicate`,
+      resourceId: `generation-dialog:${operationId}:duplicate`,
+      dialog: {
+        id: operationId,
+        mode: 'quick-edit',
+        prompt: '完美像素',
+        status: 'generating',
+        composerOpen: false,
+      },
+    });
+
+    expect(
+      inspectPerfectPixelProjectSnapshot(project, {
+        operationId,
+        taskId: `pixel-art-snap-${operationId}`,
+      }),
+    ).toMatchObject({
+      kind: 'conflict',
+      project,
+      message: '权威项目中存在重复的完美像素占位，无法自动确认结果。',
+    });
+  });
+
   it('requires a matching task resource before a missing dialog can prove asset-only success', () => {
     const operationId = 'perfect-pixel-missing-dialog';
     const matchingProject = createPerfectPixelProject(