feat: add authentication feature

.env.example

@@ -1 +1,11 @@
-DATABASE_URL=
+DATABASE_URL=
+BETTER_AUTH_SECRET=
+BETTER_AUTH_URL=
+
+GOOGLE_CLIENT_ID=
+GOOGLE_CLIENT_SECRET=
+
+GITHUB_CLIENT_ID=
+GITHUB_CLIENT_SECRET=
+
+RESEND_API_KEY=

eslint.config.mjs

@@ -2,6 +2,7 @@ import { dirname } from 'path'
 import { fileURLToPath } from 'url'
 import { FlatCompat } from '@eslint/eslintrc'
 import eslintPluginPrettierRecommended from 'eslint-plugin-prettier/recommended'
+import unicorn from 'eslint-plugin-unicorn'
 
 const __filename = fileURLToPath(import.meta.url)
 const __dirname = dirname(__filename)
@@ -11,11 +12,40 @@ const compat = new FlatCompat({
 })
 
 const eslintConfig = [
-  ...compat.extends('next/core-web-vitals', 'next/typescript', 'plugin:naming/recommended'),
+  ...compat.extends('next/core-web-vitals', 'next/typescript'),
   {
     ignores: ['node_modules/**', '.next/**', 'out/**', 'build/**', 'next-env.d.ts'],
   },
+  {
+    plugins: {
+      unicorn,
+    },
+    rules: {
+      'unicorn/filename-case': [
+        'error',
+        {
+          case: 'kebabCase',
+          ignore: [
+            // This rule applies to filenames, not directory names.
+            // The original regexes `/^\[.*\]$/` and `/^\(.*\)$/` didn't work because
+            // they don't account for file extensions (e.g., `.tsx`).
+
+            // This updated regex correctly matches dynamic segment files
+            // like `[id].tsx` or `[...slug].tsx`.
+            /^\[.*\]\..+$/,
 
+            // This is for the uncommon case where a file is named like a route group,
+            // e.g., `(marketing).tsx`.
+            /^\(.*\)\..+$/,
+
+            // This correctly ignores files that start with an underscore,
+            // such as `_app.tsx` or private utility files.
+            /^_/,
+          ],
+        },
+      ],
+    },
+  },
   eslintPluginPrettierRecommended,
 ]