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

astro/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "greasy-sprocket-website",
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "dev": "astro dev",
+    "build": "astro build",
+    "preview": "astro preview",
+    "check": "astro check"
+  },
+  "dependencies": {
+    "astro": "^5.7.0"
+  }
+}