add eslint and fix ts issues

eslint.config.js

@@ -0,0 +1,6 @@
+import eslintPluginAstro from "eslint-plugin-astro";
+
+export default [
+  js.configs.recommended,
+  ...eslintPluginAstro.configs.recommended,
+];

package.json

@@ -13,12 +13,16 @@
   "dependencies": {
     "@astrojs/check": "^0.9.4",
     "@astrojs/tailwind": "^5.1.2",
+    "@astrojs/ts-plugin": "^1.10.4",
     "astro": "^4.16.7",
     "tailwindcss": "^3.4.14",
     "typescript": "^4.9.4"
   },
   "packageManager": "[email protected]",
   "devDependencies": {
+    "@typescript-eslint/parser": "^8.12.1",
+    "eslint": "^9.13.0",
+    "eslint-plugin-astro": "^1.3.0",
     "prettier": "^3.3.3",
     "prettier-plugin-astro": "^0.14.1"
   }