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.

src/components/custom-world-home/creationWorkShelf.test.ts

@@ -86,6 +86,58 @@ test('buildCreationWorkShelfItems attaches open and delete actions through shelf
   expect(onDeletePuzzle).toHaveBeenCalledWith(puzzleWork);
 });
 
+test('buildCreationWorkShelfItems restores persisted generation state for puzzle and match3d drafts', () => {
+  const items = buildCreationWorkShelfItems({
+    rpgItems: [],
+    bigFishItems: [],
+    puzzleItems: [
+      {
+        workId: 'puzzle:generating',
+        profileId: 'puzzle-profile-generating',
+        ownerUserId: 'user-1',
+        sourceSessionId: 'puzzle-session-generating',
+        authorDisplayName: '测试作者',
+        levelName: '生成中拼图',
+        summary: '退出产品后仍应显示生成中。',
+        themeTags: [],
+        coverImageSrc: null,
+        publicationStatus: 'draft',
+        updatedAt: '2026-05-08T00:00:00.000Z',
+        publishedAt: null,
+        publishReady: false,
+        generationStatus: 'generating',
+      },
+    ],
+    match3dItems: [
+      {
+        workId: 'match3d:generating',
+        profileId: 'match3d-profile-generating',
+        ownerUserId: 'user-1',
+        sourceSessionId: 'match3d-session-generating',
+        gameName: '生成中抓鹅',
+        themeText: '糖果厨房',
+        summary: '退出产品后仍应显示生成中。',
+        tags: [],
+        coverImageSrc: null,
+        clearCount: 18,
+        difficulty: 1,
+        publicationStatus: 'draft',
+        playCount: 0,
+        updatedAt: '2026-05-07T00:00:00.000Z',
+        publishReady: false,
+        generationStatus: 'generating',
+      },
+    ],
+  });
+
+  expect(items.find((item) => item.kind === 'puzzle')?.isGenerating).toBe(
+    true,
+  );
+  expect(items.find((item) => item.kind === 'match3d')?.isGenerating).toBe(
+    true,
+  );
+});
+
 test('buildCreationWorkShelfItems maps baby object match local drafts', () => {
   const onOpenBabyObjectMatchDetail = vi.fn();
   const onDeleteBabyObjectMatch = vi.fn();