修复跨设备画布旧快照覆盖

按用户隔离画布缓存并等待权威 revision 后开放保存
固化保存重试版本并安全处理认证重载与冲突恢复
合并迟到资源图层且隔离跨账号异步请求
强制 Web 与 External 画布写入使用 expectedRevision CAS
补充竞态回归测试并同步 OpenAPI、Skill 与技术文档

.codex/skills/genarrative-external-editor-api/SKILL.md

@@ -36,7 +36,7 @@ Prefer the bundled Python helper for runnable examples: `scripts/genarrative_ext
 | Intent | Method and path | Required fields |
 | --- | --- | --- |
 | List/create projects | `GET/POST /api/external/v1/editor/projects` | create: optional `title` |
-| Save canvas | `PATCH /api/external/v1/editor/projects/{projectId}/canvas` | `viewport`, `layers` |
+| Save canvas | `PATCH /api/external/v1/editor/projects/{projectId}/canvas` | `viewport`, `layers`, `expectedRevision` |
 | Upload local media | `POST /api/external/v1/assets/direct-upload-tickets` -> OSS form -> `POST /api/external/v1/assets/objects/confirm` | ticket: `legacyPrefix`, `fileName`; confirm: `objectKey`, `assetKind` |
 | Read private media | `GET /api/external/v1/assets/read-url` | `objectKey` or `legacyPublicPath` |
 | Image generation | `POST /api/external/v1/editor/images/generations` | `prompt` |

.codex/skills/genarrative-external-editor-api/references/api-selection.md

@@ -53,7 +53,7 @@ Ask a follow-up only when two routes could both be correct and produce different
 | Load recent project | `GET /api/external/v1/editor/projects/recent` | API Key |
 | Get/delete project | `GET` or `DELETE /api/external/v1/editor/projects/{projectId}` | `projectId` |
 | Rename project | `PATCH /api/external/v1/editor/projects/{projectId}/metadata` | `title` |
-| Save canvas layout | `PATCH /api/external/v1/editor/projects/{projectId}/canvas` | `viewport`, `layers` |
+| Save canvas layout | `PATCH /api/external/v1/editor/projects/{projectId}/canvas` | `viewport`, `layers`, `expectedRevision` |
 | Add project resource | `POST /api/external/v1/editor/projects/{projectId}/resources` | `imageSrc`, `width`, `height`, `sourceType` |
 | Create upload ticket | `POST /api/external/v1/assets/direct-upload-tickets` | `legacyPrefix`, `fileName` |
 | Confirm uploaded object | `POST /api/external/v1/assets/objects/confirm` | `objectKey`, `assetKind` |

.codex/skills/genarrative-external-editor-api/scripts/genarrative_external_api.py

@@ -270,11 +270,21 @@ class GenarrativeExternalClient:
             fields[asset_label_field] = normalize_optional_text(asset_label) or "生成素材"
         return fields
 
-    def save_canvas(self, project_id: str, viewport: dict[str, Any], layers: dict[str, Any]) -> Any:
+    def save_canvas(
+        self,
+        project_id: str,
+        viewport: dict[str, Any],
+        layers: dict[str, Any],
+        expected_revision: int,
+    ) -> Any:
         return self.request_json(
             "PATCH",
             f"/api/external/v1/editor/projects/{urllib.parse.quote(project_id, safe='')}/canvas",
-            {"viewport": viewport, "layers": layers},
+            {
+                "viewport": viewport,
+                "layers": layers,
+                "expectedRevision": expected_revision,
+            },
         )
 
     def _apply_art_spec(self, fields: dict[str, Any], prompt: str) -> str: