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>

crates/zclaw-types/src/event.rs

@@ -108,6 +108,32 @@ pub enum Event {
         source: String,
         message: String,
     },
+
+    /// A2A message sent
+    A2aMessageSent {
+        from: AgentId,
+        to: String,  // Recipient string representation
+        message_type: String,
+    },
+
+    /// A2A message received
+    A2aMessageReceived {
+        from: AgentId,
+        to: String,
+        message_type: String,
+    },
+
+    /// A2A agent discovered
+    A2aAgentDiscovered {
+        agent_id: AgentId,
+        capabilities: Vec<String>,
+    },
+
+    /// A2A capability advertised
+    A2aCapabilityAdvertised {
+        agent_id: AgentId,
+        capability: String,
+    },
 }
 
 impl Event {
@@ -131,6 +157,10 @@ impl Event {
             Event::HandTriggered { .. } => "hand_triggered",
             Event::HealthCheckFailed { .. } => "health_check_failed",
             Event::Error { .. } => "error",
+            Event::A2aMessageSent { .. } => "a2a_message_sent",
+            Event::A2aMessageReceived { .. } => "a2a_message_received",
+            Event::A2aAgentDiscovered { .. } => "a2a_agent_discovered",
+            Event::A2aCapabilityAdvertised { .. } => "a2a_capability_advertised",
         }
     }
 }