Update Match3D/image-generation docs & code

Adds/updates documentation, assets and implementation for Match3D and puzzle image generation workflows. Key changes: decision logs and pitfalls updated to prefer VectorEngine Gemini for Match3D material sheets and to require edits (multipart) for 1:1 container reference images; guidance added for when to use APIMart vs VectorEngine. .env.example clarified APIMart/Responses config. Many new public assets and PPT visuals added. Code changes across frontend and backend: updated shared contracts, server-rs match3d/puzzle/image-generation handlers, VectorEngine/OpenAI image generation clients, and multiple React components/tests to handle UI/background/container image signing, edits workflow, and puzzle UI background resolution. Added src/services/puzzle-runtime/puzzleUiBackgroundSource.ts and related test updates. Includes notes about multipart HTTP/1.1 requirement and test/verification commands in docs.

docs/technical/ADMIN_CREATION_ENTRY_SWITCH_CONFIG_2026-05-11.md

@@ -67,6 +67,8 @@ Admin Web
 
 `visible=false` 会让创作中心不展示对应入口；`open=false` 会让前端展示锁定态，并让 api-server 熔断对应玩法创作 / 运行态 API。隐藏入口但仍保留既有作品号、广场详情或试玩链路时，应只关闭 `visible`，不要关闭 `open`。
 
+当前默认配置中，`visual-novel` 暂时从创作页隐藏并关闭入口，默认种子为 `visible=false`、`open=false`。如果后续只想恢复已发布作品试玩而不恢复创作入口，需要先明确 API 熔断范围，再通过后台入口开关调整，不能在前端硬编码恢复模板 Tab。
+
 ## 注意
 
 - 前端后台页面只做管理表单，不成为配置事实源。