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.

packages/shared/src/contracts/puzzleWorkSummary.ts

@@ -2,6 +2,7 @@ import type { JsonObject } from './common';
 import type { PuzzleAnchorPack, PuzzleDraftLevel } from './puzzleAgentDraft';
 
 export type PuzzleWorkPublicationStatus = 'draft' | 'published';
+export type PuzzleWorkGenerationStatus = PuzzleDraftLevel['generationStatus'];
 
 export interface PuzzleWorkSummary {
   workId: string;
@@ -28,6 +29,7 @@ export interface PuzzleWorkSummary {
   pointIncentiveTotalPoints?: number;
   pointIncentiveClaimablePoints?: number;
   publishReady: boolean;
+  generationStatus?: PuzzleWorkGenerationStatus | null;
   levels?: PuzzleDraftLevel[];
 }