feat: Add agent workspace system and runtime management

- Add agent core modules (agent_core, factory, registry, skill_loader)
- Add runtime system for agent execution management
- Add REST API for agents, workspaces, and runtime control
- Add process supervisor for agent lifecycle management
- Add workspace template system with agent profiles
- Add frontend RuntimeView and runtime API integration
- Add per-agent skill workspaces for smoke_fullstack run
- Refactor skill system with active/installed separation

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

backend/agents/base/__init__.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+"""Base agent module for EvoTraders.
+
+提供Agent基础类、命令处理、工具守卫和钩子管理等功能。
+"""
+
+# 命令处理器 (从command_handler.py导入)
+from .command_handler import (
+    AgentCommandDispatcher,
+    CommandContext,
+    CommandHandler,
+    CommandResult,
+    create_command_dispatcher,
+)
+
+__all__ = [
+    # 命令处理
+    "AgentCommandDispatcher",
+    "CommandContext",
+    "CommandHandler",
+    "CommandResult",
+    "create_command_dispatcher",
+]