fix: 审计后续 3 项修复 — 残留清理 + FTS5 CJK + HTTP 大小限制

1. Shell Hands 残留清理 (3处):
   - message.rs: 移除过时的 zclaw_hands::slideshow 注释
   - user_profiler.rs: slideshow 偏好改为 RecentTopic
   - handStore.test.ts: 移除 speech mock 数据 (3→2)

2. zclaw-growth FTS5 CJK 查询修复:
   - sanitize_fts_query CJK 路径从精确短语改为 token OR 组合
   - "Rust 编程" → "rust" OR "编程" (之前是 "rust 编程" 精确匹配)
   - 修复 test_memory_lifecycle + test_semantic_search_ranking

3. WASM HTTP 响应大小限制:
   - Content-Length 预检 + 读取后截断 (1MB 上限)
   - read_to_string 改为显式错误处理

651 测试全通过，0 失败。

desktop/tests/store/handStore.test.ts

@@ -115,14 +115,13 @@ describe('handStore — loadHands', () => {
       hands: [
         { id: 'h1', name: 'browser', description: 'Web automation', status: 'idle', requirements_met: true, category: 'automation', icon: '🌐', tool_count: 5, metric_count: 2 },
         { id: 'h2', name: 'researcher', description: 'Deep research', status: 'running', requirements_met: true },
-        { id: 'h3', name: 'speech', description: 'TTS', requirements_met: false },
       ],
     });
 
     await useHandStore.getState().loadHands();
 
     const state = useHandStore.getState();
-    expect(state.hands).toHaveLength(3);
+    expect(state.hands).toHaveLength(2);
     expect(state.hands[0].name).toBe('browser');
     expect(state.hands[0].status).toBe('idle');
     expect(state.hands[0].toolCount).toBe(5);