release(v0.2.0): streaming, MCP protocol, Browser Hand, security enhancements

## Major Features

### Streaming Response System
- Implement LlmDriver trait with `stream()` method returning async Stream
- Add SSE parsing for Anthropic and OpenAI API streaming
- Integrate Tauri event system for frontend streaming (`stream:chunk` events)
- Add StreamChunk types: Delta, ToolStart, ToolEnd, Complete, Error

### MCP Protocol Implementation
- Add MCP JSON-RPC 2.0 types (mcp_types.rs)
- Implement stdio-based MCP transport (mcp_transport.rs)
- Support tool discovery, execution, and resource operations

### Browser Hand Implementation
- Complete browser automation with Playwright-style actions
- Support Navigate, Click, Type, Scrape, Screenshot, Wait actions
- Add educational Hands: Whiteboard, Slideshow, Speech, Quiz

### Security Enhancements
- Implement command whitelist/blacklist for shell_exec tool
- Add SSRF protection with private IP blocking
- Create security.toml configuration file

## Test Improvements
- Fix test import paths (security-utils, setup)
- Fix vi.mock hoisting issues with vi.hoisted()
- Update test expectations for validateUrl and sanitizeFilename
- Add getUnsupportedLocalGatewayStatus mock

## Documentation Updates
- Update architecture documentation
- Improve configuration reference
- Add quick-start guide updates

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

desktop/tests/store/chatStore.test.ts

@@ -8,11 +8,15 @@ import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import { useChatStore, Message, Conversation, Agent, toChatAgent } from '../../src/store/chatStore';
 import { localStorageMock } from '../setup';
 
-// Mock gateway client
-const mockChatStream = vi.fn();
-const mockChat = vi.fn();
-const mockOnAgentStream = vi.fn(() => () => {});
-const mockGetState = vi.fn(() => 'disconnected');
+// Mock gateway client - use vi.hoisted to ensure mocks are available before module import
+const { mockChatStream, mockChat, mockOnAgentStream, mockGetState } = vi.hoisted(() => {
+  return {
+    mockChatStream: vi.fn(),
+    mockChat: vi.fn(),
+    mockOnAgentStream: vi.fn(() => () => {}),
+    mockGetState: vi.fn(() => 'disconnected'),
+  };
+});
 
 vi.mock('../../src/lib/gateway-client', () => ({
   getGatewayClient: vi.fn(() => ({