Add Web Dashboard with multi-device control and callback hooks

Features:
- Web Dashboard: FastAPI-based dashboard with Vue.js frontend
  - Multi-device support (ADB, HDC, iOS)
  - Real-time WebSocket updates for task progress
  - Device management with status tracking
  - Task queue with execution controls (start/stop/re-execute)
  - Detailed task information display (thinking, actions, completion messages)
  - Screenshot viewing per device
  - LAN deployment support with configurable CORS

- Callback Hooks: Interrupt and modify task execution
  - step_callback: Called after each step with StepResult
  - before_action_callback: Called before executing action
  - Support for task interruption and dynamic task switching
  - Example scripts demonstrating callback usage

- Configuration: Environment-based configuration
  - .env file support for all settings
  - .env.example template with documentation
  - Model API configuration (base URL, model name, API key)
  - Dashboard configuration (host, port, CORS, device type)
  - Phone agent configuration (delays, max steps, language)

Technical improvements:
- Fixed forward reference issue with StepResult
- Added package exports for callback types and configs
- Enhanced dependencies with FastAPI, WebSocket support
- Thread-safe task execution with device locking
- Async WebSocket broadcasting from sync thread pool

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

.env.example

@@ -0,0 +1,110 @@
+# Phone Agent Environment Configuration
+# Copy this file to .env and fill in your values
+
+# ============================================================================
+# Model Configuration / 模型配置
+# ============================================================================
+
+# Model API base URL / 模型 API 地址
+# Default: http://localhost:8000/v1
+# For BigModel (智谱AI): https://open.bigmodel.cn/api/paas/v4
+# For ModelScope: https://api-inference.modelscope.cn/v1
+PHONE_AGENT_BASE_URL=http://localhost:8000/v1
+
+# Model name / 模型名称
+# Default: autoglm-phone-9b
+PHONE_AGENT_MODEL=autoglm-phone-9b
+
+# API key for authentication / API 密钥
+# Default: EMPTY (no authentication)
+# For BigModel: your actual API key
+PHONE_AGENT_API_KEY=EMPTY
+
+# ============================================================================
+# Agent Configuration / Agent 配置
+# ============================================================================
+
+# Maximum steps per task / 每个任务的最大步数
+PHONE_AGENT_MAX_STEPS=100
+
+# Language for system prompt / 系统提示词语言
+# Options: cn (Chinese), en (English)
+PHONE_AGENT_LANG=cn
+
+# Verbose output / 详细输出
+# Options: true, false
+PHONE_AGENT_VERBOSE=true
+
+# ============================================================================
+# Device Configuration / 设备配置
+# ============================================================================
+
+# Device ID (for multi-device setups) / 设备 ID（多设备时使用）
+# Leave empty to auto-detect / 留空则自动检测
+PHONE_AGENT_DEVICE_ID=
+
+# Device type / 设备类型
+# Options: adb (Android), hdc (HarmonyOS), ios (iPhone)
+PHONE_AGENT_DEVICE_TYPE=adb
+
+# ============================================================================
+# iOS Specific Configuration / iOS 专用配置
+# ============================================================================
+
+# WebDriverAgent URL for iOS / iOS WebDriverAgent 地址
+PHONE_AGENT_WDA_URL=http://localhost:8100
+
+# ============================================================================
+# Timing Configuration (Optional) / 时序配置（可选）
+# ============================================================================
+
+# Action delays in seconds / 动作延迟（秒）
+PHONE_AGENT_KEYBOARD_SWITCH_DELAY=1.0
+PHONE_AGENT_TEXT_INPUT_DELAY=1.0
+
+# Device delays in seconds / 设备延迟（秒）
+PHONE_AGENT_TAP_DELAY=1.0
+PHONE_AGENT_SWIPE_DELAY=1.0
+PHONE_AGENT_LAUNCH_DELAY=1.0
+
+# Connection delays in seconds / 连接延迟（秒）
+PHONE_AGENT_ADB_RESTART_DELAY=2.0
+
+# ============================================================================
+# Web Dashboard Configuration / Web 仪表板配置
+# ============================================================================
+
+# Dashboard server host / 仪表板服务器主机
+# Use 0.0.0.0 for LAN access / 使用 0.0.0.0 以支持局域网访问
+DASHBOARD_HOST=0.0.0.0
+
+# Dashboard server port / 仪表板服务器端口
+DASHBOARD_PORT=8080
+
+# Dashboard debug mode / 仪表板调试模式
+# Options: true, false
+DASHBOARD_DEBUG=false
+
+# CORS allowed origins / CORS 允许的来源
+# Comma-separated list, use * for all / 逗号分隔列表，使用 * 表示全部
+# Examples: http://localhost:3000,http://192.168.1.*
+DASHBOARD_CORS_ORIGINS=*
+
+# Default device type for dashboard / 仪表板默认设备类型
+# Options: adb, hdc, ios
+DEFAULT_DEVICE_TYPE=adb
+
+# Maximum concurrent tasks / 最大并发任务数
+MAX_CONCURRENT_TASKS=10
+
+# Task timeout in seconds / 任务超时时间（秒）
+TASK_TIMEOUT_SECONDS=300
+
+# Screenshot quality (1-100) / 截图质量 (1-100)
+SCREENSHOT_QUALITY=80
+
+# Screenshot throttle delay in milliseconds / 截图节流延迟（毫秒）
+SCREENSHOT_THROTTLE_MS=500
+
+# Maximum task history to keep / 保留的最大任务历史数
+MAX_TASK_HISTORY=100