fix(world): 审计修复——快照桥两处静默死链与签名时刻定时器泄漏

审计发现的三个真实缺陷（均为静默失败或资源泄漏）：
- dbIpcHandlers TABLE_NAME_MAP 缺 worldSnapshots 映射：快照写入抛"不在白名单"被catch吞掉，跨进程桥实际断裂。补 worldSnapshots→world_snapshots
- useWorldSnapshotSync 调用 db:query 方法 'get' 不在白名单（仅getAll/getById/count），同样静默失败。改用 getById
- SignatureMoment reduced-motion 路径提前 return 丢失 cleanup，卸载后定时器仍触发 setState。重构为 if/else 统一 return clearTimers

Author: Aparencia

client/electron/db/dbIpcHandlers.ts

@@ -77,6 +77,8 @@ const TABLE_NAME_MAP: Record<string, string> = {
   crdtChanges: 'crdt_changes',
   // v6 新增：A4 实施意图
   implementationIntentions: 'implementation_intentions',
+  // v7 新增：世界状态快照（MCP 记忆接口跨进程桥）
+  worldSnapshots: 'world_snapshots',
 };
 
 function resolveTable(table: string): string {

client/src/features/retention/components/SignatureMoment.tsx

@@ -74,15 +74,15 @@ export function SignatureMoment() {
       setAct('event');
       soundPlayer.play('achievement_unlocked');
       timers.current.push(setTimeout(dismiss, STATIC_MS));
-      return;
+    } else {
+      setAct('silence');
+      soundPlayer.play('achievement_unlocked');
+      timers.current.push(setTimeout(() => setAct('event'), ACT1_MS));
+      timers.current.push(setTimeout(() => setAct('afterglow'), ACT1_MS + ACT2_MS));
+      timers.current.push(setTimeout(dismiss, ACT1_MS + ACT2_MS + ACT3_MS));
     }
 
-    setAct('silence');
-    soundPlayer.play('achievement_unlocked');
-    timers.current.push(setTimeout(() => setAct('event'), ACT1_MS));
-    timers.current.push(setTimeout(() => setAct('afterglow'), ACT1_MS + ACT2_MS));
-    timers.current.push(setTimeout(dismiss, ACT1_MS + ACT2_MS + ACT3_MS));
-
+    // 两条路径都必须清理：防止卸载后定时器触发 setState
     return clearTimers;
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [signatureSeq]);

client/src/features/retention/hooks/useWorldSnapshotSync.ts

@@ -40,8 +40,8 @@ export function useWorldSnapshotSync(): void {
       });
       const row = { id: SNAPSHOT_ID, payload, updated_at: new Date().toISOString() };
       try {
-        // 先查后写实现 upsert（db 桥无 put 语义）
-        const existing = await window.electronAPI.db.query('worldSnapshots', 'get', [SNAPSHOT_ID]);
+        // 先查后写实现 upsert（db 桥查询方法白名单为 getAll/getById/count）
+        const existing = await window.electronAPI.db.query('worldSnapshots', 'getById', [SNAPSHOT_ID]);
         if (existing) {
           await window.electronAPI.db.update('worldSnapshots', SNAPSHOT_ID, {
             payload, updated_at: row.updated_at,