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>

internal/config/config_test.go

@@ -200,8 +200,8 @@ func TestGRPCSocketPath(t *testing.T) {
 		addr string
 		want string
 	}{
-		{"/var/run/mc-proxy.sock", "/var/run/mc-proxy.sock"},
-		{"unix:/var/run/mc-proxy.sock", "/var/run/mc-proxy.sock"},
+		{"/srv/mc-proxy/mc-proxy.sock", "/srv/mc-proxy/mc-proxy.sock"},
+		{"unix:/srv/mc-proxy/mc-proxy.sock", "/srv/mc-proxy/mc-proxy.sock"},
 	}
 	for _, tt := range tests {
 		g := GRPC{Addr: tt.addr}
@@ -220,7 +220,7 @@ func TestValidateGRPCUnixSocket(t *testing.T) {
 path = "/tmp/test.db"
 
 [grpc]
-addr = "/var/run/mc-proxy.sock"
+addr = "/srv/mc-proxy/mc-proxy.sock"
 `
 	if err := os.WriteFile(path, []byte(data), 0600); err != nil {
 		t.Fatalf("write config: %v", err)