Add mcp route command for managing mc-proxy routes

New top-level command with list, add, remove subcommands. Supports
-n/--node to target a specific node. Adds AddProxyRoute and
RemoveProxyRoute RPCs to the agent. Moves route listing from
mcp node routes to mcp route list.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

proto/mcp/v1/mcp.proto

@@ -39,6 +39,8 @@ service McpAgentService {
 
   // Proxy routes (query mc-proxy)
   rpc ListProxyRoutes(ListProxyRoutesRequest) returns (ListProxyRoutesResponse);
+  rpc AddProxyRoute(AddProxyRouteRequest) returns (AddProxyRouteResponse);
+  rpc RemoveProxyRoute(RemoveProxyRouteRequest) returns (RemoveProxyRouteResponse);
 
   // Logs
   rpc Logs(LogsRequest) returns (stream LogsResponse);
@@ -353,3 +355,20 @@ message ListProxyRoutesResponse {
   google.protobuf.Timestamp started_at = 3;
   repeated ProxyListenerInfo listeners = 4;
 }
+
+message AddProxyRouteRequest {
+  string listener_addr = 1;  // e.g. ":443"
+  string hostname = 2;
+  string backend = 3;
+  string mode = 4;           // "l4" or "l7"
+  bool backend_tls = 5;
+}
+
+message AddProxyRouteResponse {}
+
+message RemoveProxyRouteRequest {
+  string listener_addr = 1;  // e.g. ":443"
+  string hostname = 2;
+}
+
+message RemoveProxyRouteResponse {}