feat: 实现多主机架构的核心组件

新增路由器、主机客户端和共享协议模块，支持多主机部署模式：
- 路由器作为中央节点管理主机连接和消息路由
- 主机客户端作为工作节点运行本地代理
- 共享协议定义通信消息格式
- 新增独立运行模式standalone.py
- 更新配置系统支持路由模式

bot/commands.py

@@ -67,6 +67,8 @@ async def handle_command(user_id: str, text: str) -> Optional[str]:
         return await _cmd_shell(args)
     elif cmd == "/remind":
         return await _cmd_remind(args)
+    elif cmd in ("/nodes", "/node"):
+        return await _cmd_nodes(user_id, args)
     else:
         return None
 
@@ -278,6 +280,39 @@ async def _cmd_remind(args: str) -> str:
     return f"⏰ Reminder #{job_id} set for {value}{unit} from now"
 
 
+async def _cmd_nodes(user_id: str, args: str) -> str:
+    """List nodes or switch active node."""
+    from config import ROUTER_MODE
+    if not ROUTER_MODE:
+        return "Not in router mode. Run standalone.py for multi-host support."
+
+    from router.nodes import get_node_registry
+    registry = get_node_registry()
+
+    if args:
+        args = args.strip()
+        if registry.set_active_node(user_id, args):
+            return f"✓ Active node set to: {args}"
+        return f"Error: Node '{args}' not found"
+
+    nodes = registry.list_nodes()
+    if not nodes:
+        return "No nodes connected."
+
+    active_node_id = None
+    active_node = registry.get_active_node(user_id)
+    if active_node:
+        active_node_id = active_node.node_id
+
+    lines = ["**Connected Nodes:**\n"]
+    for n in nodes:
+        marker = "→ " if n["node_id"] == active_node_id else "  "
+        status = "🟢" if n["status"] == "online" else "🔴"
+        lines.append(f"{marker}{n['display_name']} {status}  sessions={n['sessions']}")
+    lines.append("\nUse `/node <name>` to switch active node.")
+    return "\n".join(lines)
+
+
 def _cmd_help() -> str:
     """Show help."""
     return """**Commands:**
@@ -290,5 +325,7 @@ def _cmd_help() -> str:
 /shell <cmd> - Run shell command (bypasses LLM)
 /remind <time> <msg> - Set reminder (e.g. /remind 10m check build)
 /tasks - List background tasks
+/nodes - List connected host nodes
+/node <name> - Switch active node
 /retry - Retry last message
 /help - Show this help"""

bot/handler.py

@@ -86,7 +86,7 @@ def _handle_message(data: P2ImMessageReceiveV1) -> None:
 
 
 async def _process_message(user_id: str, chat_id: str, text: str) -> None:
-    """Process message: check allowlist, then commands, then agent."""
+    """Process message: check allowlist, then commands, then route to node or local agent."""
     try:
         set_current_chat(chat_id)
 
@@ -96,10 +96,48 @@ async def _process_message(user_id: str, chat_id: str, text: str) -> None:
             return
 
         reply = await handle_command(user_id, text)
-        if reply is None:
+        if reply is not None:
+            if reply:
+                await send_text(chat_id, "chat_id", reply)
+            return
+
+        from config import ROUTER_MODE
+        if ROUTER_MODE:
+            from router.routing_agent import route
+            from router.rpc import forward
+            from router.nodes import get_node_registry
+
+            node_id, reason = await route(user_id, chat_id, text)
+
+            if node_id is None:
+                await send_text(chat_id, "chat_id", f"No host available: {reason}")
+                return
+
+            if node_id == "meta":
+                registry = get_node_registry()
+                nodes = registry.list_nodes()
+                if nodes:
+                    lines = ["Connected Nodes:"]
+                    for n in nodes:
+                        marker = " → " if n.get("node_id") == registry.get_active_node(user_id) else "   "
+                        lines.append(f"{marker}{n['display_name']}  sessions={n['sessions']}  {n['status']}")
+                    lines.append("\nUse \"/node <name>\" to switch active node.")
+                    await send_text(chat_id, "chat_id", "\n".join(lines))
+                else:
+                    await send_text(chat_id, "chat_id", "No nodes connected.")
+                return
+
+            try:
+                reply = await forward(node_id, user_id, chat_id, text)
+                if reply:
+                    await send_text(chat_id, "chat_id", reply)
+            except Exception as e:
+                logger.exception("Failed to forward to node %s", node_id)
+                await send_text(chat_id, "chat_id", f"Error communicating with node: {e}")
+        else:
             reply = await agent.run(user_id, text)
-        if reply:
-            await send_text(chat_id, "chat_id", reply)
+            if reply:
+                await send_text(chat_id, "chat_id", reply)
     except Exception:
         logger.exception("Error processing message for user %s", user_id)