feat: initial Greasy Sprocket website — Astro static + Go feedback service

- Astro 5.x static site with content collections for extensions
- Pages: index, [slug] (per-extension), coffee (Ko-fi), feedback form
- Go binary gs-feedback: SQLite storage + Discord webhook notification
- Nginx config: static serving + POST proxy to Go backend
- Deploy script: build + rsync to VPS
- ThockBoard landing page with features and sound pack listing

deploy/gs-feedback.service

@@ -0,0 +1,24 @@
+[Unit]
+Description=Greasy Sprocket Feedback Service
+After=network.target
+
+[Service]
+Type=simple
+ExecStart=/usr/local/bin/gs-feedback
+Environment=GS_PORT=8080
+Environment=GS_DB_PATH=/var/lib/gs-feedback/feedback.db
+Environment=GS_DISCORD_WEBHOOK=__DISCORD_WEBHOOK_URL__
+Restart=on-failure
+RestartSec=5
+User=www-data
+Group=www-data
+
+# Security
+NoNewPrivileges=true
+ProtectSystem=strict
+ProtectHome=true
+ReadWritePaths=/var/lib/gs-feedback
+PrivateTmp=true
+
+[Install]
+WantedBy=multi-user.target