feat: complete Phase 1-3 architecture optimization

Phase 1 - Security:
- Add AES-GCM encryption for localStorage fallback
- Enforce WSS protocol for non-localhost WebSocket connections
- Add URL sanitization to prevent XSS in markdown links

Phase 2 - Domain Reorganization:
- Create Intelligence Domain with Valtio store and caching
- Add unified intelligence-client for Rust backend integration
- Migrate from legacy agent-memory, heartbeat, reflection modules

Phase 3 - Core Optimization:
- Add virtual scrolling for ChatArea with react-window
- Implement LRU cache with TTL for intelligence operations
- Add message virtualization utilities

Additional:
- Add OpenFang compatibility test suite
- Update E2E test fixtures
- Add audit logging infrastructure
- Update project documentation and plans

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

desktop/tests/e2e/fixtures/mock-gateway.ts

@@ -746,17 +746,6 @@ export async function mockAgentMessageResponse(page: Page, response: string): Pr
   });
 }
 
-/**
- * Create a mock agent message response object
- */
-function createAgentMessageResponse(content: string): object {
-  return {
-    response: content,
-    input_tokens: 100,
-    output_tokens: content.length,
-  };
-}
-
 /**
  * Mock 错误响应
  */