Add EmDash CMS blog + hero standardization + seed fix

- Add EmDash CMS integration with SQLite and local storage
- Add blog collection (seed/seed.json) with 3 sample posts
- Add /บทความ list page and /บทความ/[slug] detail page
- Add blog section to homepage
- Fix reserved field slugs (slug, published_at removed from fields)
- Fix date field mapping (publishedAt camelCase)
- Fix featured image URL for admin-uploaded images (meta.storageKey)
- Standardize all product page hero sections
- Update navigation with 'บทความ' link
- Configure Google OAuth provider

package.json

@@ -7,14 +7,20 @@
     "dev": "astro dev",
     "build": "astro build",
     "preview": "astro preview",
-    "astro": "astro"
+    "astro": "astro",
+    "start": "node ./dist/server/entry.mjs"
   },
   "dependencies": {
     "@astrojs/check": "^0.9.4",
+    "@astrojs/node": "^10.1.1",
+    "@astrojs/react": "^5.0.5",
     "@tailwindcss/typography": "^0.5.15",
     "@tailwindcss/vite": "^4.0.0",
     "astro": "^6.1.7",
+    "emdash": "^0.14.0",
     "marked": "^18.0.3",
+    "react": "^19.2.6",
+    "react-dom": "^19.2.6",
     "tailwindcss": "^4.0.0",
     "typescript": "^5.6.3"
   },