Add generationStatus and match3d/runtime fixes

Introduce persistent generationStatus to work summaries (puzzle & match3d) and propagate generation recovery rules across docs and frontend/backends so "generating" is restored from server-side work summary rather than ephemeral front-end notices. Update API server image/asset handling (improve match3d material sheet green/alpha decontamination and promote generatedItemAssets background fields) and add runtime improvements: alpha-based hotspot hit-testing, tray insertion/three-match animation behavior, and session re-read on client-side VectorEngine timeouts/lock-screen interruptions. Many docs, tests and related frontend modules updated/added to reflect these contract and behavior changes.

.hermes/shared-memory/decision-log.md

@@ -16,6 +16,14 @@
 
 ---
 
+## 2026-05-16 草稿生成中态由后端作品摘要恢复
+
+- 背景：草稿作品在生成中时，用户退出或刷新页面后，如果前端只依赖内存 notice，生成遮罩会丢失，作品架会误显示为普通草稿。
+- 决策：作品架与入口壳层恢复生成中态时，统一以后端 work summary 下发的 `generationStatus` 为准；前端内存 notice 只承担本轮会话的即时反馈。拼图草稿在结果页编译时会把 `generating` 写回可持久化的 work profile 关卡状态，抓大鹅草稿则通过 work summary 的素材完整性回推生成态。
+- 影响范围：草稿页作品架、平台入口壳层、拼图 / 抓大鹅 work summary 契约与后端编排。
+- 验证方式：刷新或重新进入产品后，仍可从 `generationStatus=generating` 恢复等待遮罩；相关测试见 `creationWorkShelf.test.ts`、拼图 / 抓大鹅 works 合约测试与后端编排测试。
+- 关联文档：`docs/【玩法创作】平台入口与玩法链路-2026-05-15.md`。
+
 ## 2026-05-15 抓大鹅结果页 UI 预览复用运行态布局
 
 - 背景：抓大鹅结果页 `素材配置 > UI` 的预览弹层曾手写简化 HUD 和容器布局，和真实运行态顶部关卡卡片、右上设置入口、容器图定位及槽位样式出现漂移。