Implement Astro features: React Islands, Server Endpoints, i18n, Partytown

Features added:
- React integration with @astrojs/react
- React components: DMRDashboard, MemberSearch
- API endpoints: /api/repeaters.json, /api/dmr-contacts.json, /api/feed/[category].xml
- i18n support for TR/EN locales with LanguageSwitcher component
- Partytown enabled for third-party script optimization
- Admin panel logo fixed (moved to public/images/)

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

tsconfig.json

@@ -5,9 +5,18 @@
     "allowJs": true,
     "baseUrl": ".",
     "paths": {
-      "~/*": ["src/*"]
-    }
+      "~/*": [
+        "src/*"
+      ]
+    },
+    "jsx": "react-jsx",
+    "jsxImportSource": "react"
   },
-  "include": [".astro/types.d.ts", "**/*"],
-  "exclude": ["dist/"]
-}
+  "include": [
+    ".astro/types.d.ts",
+    "**/*"
+  ],
+  "exclude": [
+    "dist/"
+  ]
+}