Add undeploy command: full inverse of deploy

Implements `mcp undeploy <service>` which tears down all infrastructure
for a service: removes mc-proxy routes, DNS records, TLS certificates,
stops and removes containers, releases allocated ports, and marks the
service inactive.

This fills the gap between `stop` (temporary pause) and `purge` (registry
cleanup). Undeploy is the complete teardown that returns the node to the
state before the service was deployed.

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

proto/mcp/v1/mcp.proto

@@ -8,6 +8,7 @@ import "google/protobuf/timestamp.proto";
 service McpAgentService {
   // Service lifecycle
   rpc Deploy(DeployRequest) returns (DeployResponse);
+  rpc UndeployService(UndeployServiceRequest) returns (UndeployServiceResponse);
   rpc StopService(StopServiceRequest) returns (StopServiceResponse);
   rpc StartService(StartServiceRequest) returns (StartServiceResponse);
   rpc RestartService(RestartServiceRequest) returns (RestartServiceResponse);
@@ -102,6 +103,14 @@ message RestartServiceResponse {
   repeated ComponentResult results = 1;
 }
 
+message UndeployServiceRequest {
+  string name = 1;
+}
+
+message UndeployServiceResponse {
+  repeated ComponentResult results = 1;
+}
+
 // --- Desired state ---
 
 message SyncDesiredStateRequest {