Add status command, deployment infrastructure, and fix proto paths

Rename proto/gen directories from mc-proxy to mc_proxy for valid protobuf
package naming. Add CLI status subcommand for querying running instance
health via gRPC. Add systemd backup service/timer and backup pruning
script. Add buf.yaml and proto-lint Makefile target. Add shutdown_timeout
config field.

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

deploy/systemd/mc-proxy-backup.service

@@ -0,0 +1,25 @@
+[Unit]
+Description=mc-proxy database backup
+After=mc-proxy.service
+
+[Service]
+Type=oneshot
+User=mc-proxy
+Group=mc-proxy
+ExecStart=/usr/local/bin/mc-proxy snapshot --config /srv/mc-proxy/mc-proxy.toml
+ExecStartPost=/usr/bin/find /srv/mc-proxy/backups -name "mc-proxy-*.db" -type f -mtime +30 -delete
+
+NoNewPrivileges=true
+ProtectSystem=strict
+ProtectHome=true
+PrivateTmp=true
+PrivateDevices=true
+ProtectKernelTunables=true
+ProtectKernelModules=true
+ProtectControlGroups=true
+RestrictSUIDSGID=true
+RestrictNamespaces=true
+LockPersonality=true
+MemoryDenyWriteExecute=true
+RestrictRealtime=true
+ReadWritePaths=/srv/mc-proxy

deploy/systemd/mc-proxy-backup.timer

@@ -0,0 +1,10 @@
+[Unit]
+Description=Daily mc-proxy database backup
+
+[Timer]
+OnCalendar=*-*-* 02:00:00 UTC
+RandomizedDelaySec=300
+Persistent=true
+
+[Install]
+WantedBy=timers.target