Serve the prerendered site from Node instead of nginx root.

Avoids www-data traversing the cashumints tree and keeps rebuilds from blanking a live root.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/package.json

@@ -8,6 +8,7 @@
     "og": "node scripts/og/build-og.mjs",
     "og:fixtures": "node scripts/og/build-og.mjs --fixtures",
     "build": "node scripts/og/build-og.mjs && astro build",
+    "start": "node server.mjs",
     "preview": "astro preview",
     "typecheck": "astro check",
     "bones": "node --env-file-if-exists=../.env scripts/bones.mjs",