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>

hands/whiteboard.HAND.toml

@@ -0,0 +1,125 @@
+# Whiteboard Hand - 白板绘制能力包
+#
+# ZCLAW Hand 配置
+# 提供交互式白板绘制能力，支持文本、图形、公式、图表等
+
+[hand]
+name = "whiteboard"
+version = "1.0.0"
+description = "白板绘制能力包 - 绘制文本、图形、公式、图表等教学内容"
+author = "ZCLAW Team"
+
+type = "presentation"
+requires_approval = false
+timeout = 60
+max_concurrent = 1
+
+tags = ["whiteboard", "drawing", "presentation", "education", "teaching"]
+
+[hand.config]
+# 画布尺寸
+canvas_width = 1920
+canvas_height = 1080
+
+# 默认画笔颜色
+default_color = "#333333"
+
+# 默认线宽
+default_line_width = 2
+
+# 支持的绘制动作
+supported_actions = [
+  "draw_text",
+  "draw_shape",
+  "draw_line",
+  "draw_chart",
+  "draw_latex",
+  "draw_table",
+  "erase",
+  "clear",
+  "undo",
+  "redo"
+]
+
+# 字体配置
+[hand.config.fonts]
+text_font = "system-ui"
+math_font = "KaTeX_Main"
+code_font = "JetBrains Mono"
+
+[hand.triggers]
+manual = true
+schedule = false
+webhook = false
+
+[[hand.triggers.events]]
+type = "chat.intent"
+pattern = "画|绘制|白板|展示|draw|whiteboard|sketch"
+priority = 5
+
+[hand.permissions]
+requires = [
+  "whiteboard.draw",
+  "whiteboard.clear",
+  "whiteboard.export"
+]
+
+roles = ["operator.read"]
+
+[hand.rate_limit]
+max_requests = 100
+window_seconds = 3600
+
+[hand.audit]
+log_inputs = true
+log_outputs = false  # 绘制内容不记录
+retention_days = 7
+
+# 绘制动作定义
+[[hand.actions]]
+id = "draw_text"
+name = "绘制文本"
+description = "在白板上绘制文本"
+params = { x = "number", y = "number", text = "string", font_size = "number?", color = "string?" }
+
+[[hand.actions]]
+id = "draw_shape"
+name = "绘制图形"
+description = "绘制矩形、圆形、箭头等基本图形"
+params = { shape = "string", x = "number", y = "number", width = "number", height = "number", fill = "string?" }
+
+[[hand.actions]]
+id = "draw_line"
+name = "绘制线条"
+description = "绘制直线或曲线"
+params = { points = "array", color = "string?", line_width = "number?" }
+
+[[hand.actions]]
+id = "draw_chart"
+name = "绘制图表"
+description = "绘制柱状图、折线图、饼图等"
+params = { chart_type = "string", data = "object", x = "number", y = "number", width = "number", height = "number" }
+
+[[hand.actions]]
+id = "draw_latex"
+name = "绘制公式"
+description = "渲染 LaTeX 数学公式"
+params = { latex = "string", x = "number", y = "number", font_size = "number?" }
+
+[[hand.actions]]
+id = "draw_table"
+name = "绘制表格"
+description = "绘制数据表格"
+params = { headers = "array", rows = "array", x = "number", y = "number" }
+
+[[hand.actions]]
+id = "clear"
+name = "清空画布"
+description = "清空白板所有内容"
+params = {}
+
+[[hand.actions]]
+id = "export"
+name = "导出图片"
+description = "将白板内容导出为图片"
+params = { format = "string?" }