Switch to VectorEngine gpt-image-2 and edits

Replace uses of the legacy `gpt-image-2-all` model with `gpt-image-2` and standardize image workflows: no-reference generation uses POST /v1/images/generations, any-reference flows use POST /v1/images/edits with multipart `image` parts. Update SKILLs, generation scripts, decision logs, and docs to reflect the contract change and edits-vs-generations guidance. Apply corresponding changes across backend (api-server match3d/puzzle modules, openai image adapter, mappers, telemetry, spacetime client/module), frontend components and services (Match3D, Puzzle, CreativeImageInputPanel, runtime shells), and add new spritesheet/parser files and tests. Also add media/logo.png. These changes align repository code and documentation with the VectorEngine image API contract and update generation/upload handling (green-screen -> alpha processing, spritesheet handling, and related tests).

docs/technical/CHILD_MOTION_DEMO_WARMUP_IMPLEMENTATION_SPEC_2026-05-09.md

@@ -1,4 +1,4 @@
-# 儿童动作识别互动玩法 Demo 热身关开发规格文档
+# 儿童动作识别互动玩法 Demo 热身关开发规格文档
 
 > 日期：2026-05-09
 > 关联设计文档：[CHILD_MOTION_DEMO_WARMUP_LEVEL_DESIGN_2026-05-09.md](../design/CHILD_MOTION_DEMO_WARMUP_LEVEL_DESIGN_2026-05-09.md)
@@ -684,7 +684,7 @@
 1. 舞台主环境采用卡通绘本风格、明亮草地、天空、小山坡和树木的组合，默认背景环境需要保证中心与下方前景留空，便于角色轮廓和地面指示环叠加。
 2. 该卡通绘本草地风格是儿童动作 Demo 后续场景、物品、UI 资源的全局风格要求；新增资源不得切回暗色科技风、真实照片风或后台面板风。
 3. `src/index.css` 中的热身舞台、摄像头背景层、地面、角色轮廓、地面圆环、开始按钮和横屏提示均按绘本草地风格接入真实资源；资源加载失败时保留 CSS 兜底。
-4. 生成脚本固定为 `scripts/generate-child-motion-demo-assets.mjs`，并通过 `npm run assets:child-motion-demo` 触发；脚本使用 `gpt-image-2-all` 调用 VectorEngine `POST /v1/images/generations`，透明资源先生成品红底源图，再在本地移除色键，源图写入 `tmp/child-motion-demo-assets/`。
+4. 生成脚本固定为 `scripts/generate-child-motion-demo-assets.mjs`，并通过 `npm run assets:child-motion-demo` 触发；脚本使用 `gpt-image-2` 调用 VectorEngine `POST /v1/images/generations`，透明资源先生成品红底源图，再在本地移除色键，源图写入 `tmp/child-motion-demo-assets/`。
 5. 当前已生成并接入以下正式 Demo 资源：
    - `public/child-motion-demo/picture-book-grass-stage.png`：默认草地舞台背景。
    - `public/child-motion-demo/picture-book-foreground-grass-v2.png`：底部前景草坪条，只覆盖舞台下沿，不作为整块地板拉伸。