修复外部图片接口绕过场景合同

统一主站与外部图片生成的场景边界校验
新增场景伪装请求零入队回归测试
同步外部OpenAPI、Skill与场景技术文档

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

@@ -88,6 +88,7 @@ Use video/audio reference arrays only with models that support them. Do not pass
 Use OpenAPI as the final authority; these common values are a routing aid:
 
 - Image `kind`: `spec`, `character`, `quick-edit`, `ui-design`, `publication-material`; ordinary image generation may omit it.
+- External v1 currently has no structured game-scene generation operation. Do not send `kind: "scene"` or `assetKind: "scene"` through generic image generation; the server rejects both before queueing.
 - Image `model`: `gpt-image-2`, `gemini-3.1-flash-image-preview`, `nanobanana2`, `nano-banana`.
 - Image `aspectRatio`: `1:1`, `2:3`, `3:2`, `9:16`, `16:9`.
 - Image `imageSize`: `0.5K`, `1K`, `2K`.

.codex/skills/genarrative-external-editor-api/references/requests-and-outputs.md

@@ -104,6 +104,8 @@ For the lower-level asset/resource creation endpoints, `generationInputs` is rep
 
 ## Art Spec and Image Request
 
+Generic External v1 image generation does not expose the main-site structured game-scene contract. `kind: "scene"` and `assetKind: "scene"` are both invalid and return HTTP `400` before any generation job is queued. Do not replace the structured scene fields and server-owned prompt assembly with a generic image prompt.
+
 Carry the current art spec in `generationInputs.artSpec` and reflect important constraints in the prompt:
 
 ```json