feat(website): add Nerd Fonts for programming language icons

- Add Monaspace Argon NF font for dev icons
- Update cookbook.yml with unicode codepoints for language icons:
  - TypeScript: \uE628
  - Python: \uE73C
  - C#/.NET: \uF81A
  - Go: \uE626
- Style .lang-tab and .lang-indicator with Nerd Font family

website/public/data/samples.json

@@ -10,25 +10,25 @@
         {
           "id": "nodejs",
           "name": "Node.js / TypeScript",
-          "icon": "🟢",
+          "icon": "",
           "extension": ".ts"
         },
         {
           "id": "python",
           "name": "Python",
-          "icon": "🐍",
+          "icon": "",
           "extension": ".py"
         },
         {
           "id": "dotnet",
           "name": ".NET (C#)",
-          "icon": "🟣",
+          "icon": "",
           "extension": ".cs"
         },
         {
           "id": "go",
           "name": "Go",
-          "icon": "🔵",
+          "icon": "",
           "extension": ".go"
         }
       ],