Add per-route details to status, move socket to /srv/mc-proxy/

mcproxyctl status now shows individual routes per listener with
hostname, backend, mode, and re-encrypt indicator. Proto, gRPC
server, client library, and CLI all updated.

Default gRPC socket path moved from /var/run/mc-proxy.sock to
/srv/mc-proxy/mc-proxy.sock to match the service data directory
convention.

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

client/mcproxy/doc.go

@@ -5,7 +5,7 @@
 //
 // # Basic Usage
 //
-//	client, err := mcproxy.Dial("/var/run/mc-proxy.sock")
+//	client, err := mcproxy.Dial("/srv/mc-proxy/mc-proxy.sock")
 //	if err != nil {
 //	    log.Fatal(err)
 //	}