feat: add OG images, favicon set, manifest and performance tuning

- Build-time Open Graph cards per post and a default card (Satori + Sharp)
- Favicon/ICO/apple-touch/manifest icons generated from one SVG (npm run icons)
- robots.txt and web manifest generated from site.json
- Subset self-hosted fonts to Latin + Turkish (188 KB -> 66 KB) with preload
- Inline the stylesheet to remove the render-blocking request
- Post-build site audit (npm run check:site): h1, alt, SEO tags, links
- Omit canonical on noindex pages

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -13,7 +13,10 @@
     "format": "prettier --write .",
     "format:check": "prettier --check .",
     "new:post": "node scripts/new-post.mjs",
-    "astro": "astro"
+    "astro": "astro",
+    "icons": "node scripts/generate-icons.mjs",
+    "check:site": "node scripts/check-site.mjs",
+    "fonts": "node scripts/subset-fonts.mjs"
   },
   "dependencies": {
     "@astrojs/markdown-satteri": "^0.4.4",
@@ -21,8 +24,6 @@
     "@astrojs/node": "^11.1.8",
     "@astrojs/rss": "^4.0.19",
     "@astrojs/sitemap": "^3.7.4",
-    "@fontsource-variable/inter": "^5.3.0",
-    "@fontsource-variable/rubik": "^5.3.0",
     "@iconify-json/tabler": "^1.2.42",
     "@tailwindcss/vite": "^4.3.3",
     "astro": "^7.4.0",
@@ -32,12 +33,19 @@
   },
   "devDependencies": {
     "@astrojs/check": "^0.9.10",
+    "@fontsource-variable/inter": "^5.3.0",
+    "@fontsource-variable/rubik": "^5.3.0",
+    "@fontsource/inter": "^5.3.0",
+    "@fontsource/rubik": "^5.3.0",
     "@tailwindcss/typography": "^0.5.20",
     "@types/leaflet": "^1.9.22",
     "pagefind": "^1.5.2",
     "prettier": "^3.9.10",
     "prettier-plugin-astro": "^1.1.1",
     "prettier-plugin-tailwindcss": "^0.8.1",
+    "satori": "^0.60.0",
+    "sharp": "^0.35.5",
+    "subset-font": "^2.9.0",
     "typescript": "^6.0.3"
   }
 }