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

.gitignore

@@ -0,0 +1,19 @@
+# Dependencies
+node_modules/
+astro/.astro/
+astro/dist/
+
+# Go build artifacts
+feedback-svc/bin/
+
+# Environment
+.env
+*.env
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Editor
+.vscode/
+.idea/