Add Gitea Actions CI and release workflows and deployment assets

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

deploy/hammerhead.service

@@ -0,0 +1,26 @@
+[Unit]
+Description=Hammerhead: control plane for tunnelled ports and websites
+Documentation=https://git.veillax.com/Veillax/hammerhead
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+User=hammerhead
+Group=hammerhead
+EnvironmentFile=-/etc/hammerhead/hammerhead.env
+ExecStart=/usr/local/bin/hammerhead -listen :8080 -data /var/lib/hammerhead
+WorkingDirectory=/var/lib/hammerhead
+Restart=on-failure
+RestartSec=3
+
+# It only needs its own data folder and the network.
+NoNewPrivileges=true
+ProtectSystem=strict
+ReadWritePaths=/var/lib/hammerhead
+ProtectHome=true
+PrivateTmp=true
+ProtectKernelTunables=true
+ProtectControlGroups=true
+
+[Install]
+WantedBy=multi-user.target