refactor: migrate to eslint flat config and format codebase with prettier

- Remove legacy .eslintrc.cjs and .eslintignore
- Add eslint.config.js with flat config, security rules (no-eval, no-implied-eval, no-new-func, no-script-url)
- Add .prettierrc and .prettierignore
- Format entire codebase with prettier

src/pages/TelegramCallback.tsx

@@ -1,44 +1,44 @@
-import { useEffect, useState } from 'react'
-import { useNavigate, useSearchParams } from 'react-router-dom'
-import { useTranslation } from 'react-i18next'
-import { useAuthStore } from '../store/auth'
+import { useEffect, useState } from 'react';
+import { useNavigate, useSearchParams } from 'react-router-dom';
+import { useTranslation } from 'react-i18next';
+import { useAuthStore } from '../store/auth';
 
 export default function TelegramCallback() {
-  const { t } = useTranslation()
-  const navigate = useNavigate()
-  const [searchParams] = useSearchParams()
-  const [error, setError] = useState('')
-  const { loginWithTelegramWidget, isAuthenticated } = useAuthStore()
+  const { t } = useTranslation();
+  const navigate = useNavigate();
+  const [searchParams] = useSearchParams();
+  const [error, setError] = useState('');
+  const { loginWithTelegramWidget, isAuthenticated } = useAuthStore();
 
   useEffect(() => {
     if (isAuthenticated) {
-      navigate('/')
-      return
+      navigate('/');
+      return;
     }
 
     const authenticate = async () => {
       // Get auth data from URL params
-      const id = searchParams.get('id')
-      const firstName = searchParams.get('first_name')
-      const lastName = searchParams.get('last_name')
-      const username = searchParams.get('username')
-      const photoUrl = searchParams.get('photo_url')
-      const authDate = searchParams.get('auth_date')
-      const hash = searchParams.get('hash')
+      const id = searchParams.get('id');
+      const firstName = searchParams.get('first_name');
+      const lastName = searchParams.get('last_name');
+      const username = searchParams.get('username');
+      const photoUrl = searchParams.get('photo_url');
+      const authDate = searchParams.get('auth_date');
+      const hash = searchParams.get('hash');
 
       // Validate required fields
       if (!id || !firstName || !authDate || !hash) {
-        setError(t('auth.telegramRequired'))
-        return
+        setError(t('auth.telegramRequired'));
+        return;
       }
 
       // Parse and validate numeric fields
-      const parsedId = parseInt(id, 10)
-      const parsedAuthDate = parseInt(authDate, 10)
+      const parsedId = parseInt(id, 10);
+      const parsedAuthDate = parseInt(authDate, 10);
 
       if (Number.isNaN(parsedId) || Number.isNaN(parsedAuthDate)) {
-        setError(t('auth.telegramRequired'))
-        return
+        setError(t('auth.telegramRequired'));
+        return;
       }
 
       try {
@@ -50,46 +50,39 @@ export default function TelegramCallback() {
           photo_url: photoUrl || undefined,
           auth_date: parsedAuthDate,
           hash: hash,
-        })
-        navigate('/')
+        });
+        navigate('/');
       } catch (err: unknown) {
-        const error = err as { response?: { data?: { detail?: string } } }
-        setError(error.response?.data?.detail || t('common.error'))
+        const error = err as { response?: { data?: { detail?: string } } };
+        setError(error.response?.data?.detail || t('common.error'));
       }
-    }
+    };
 
-    authenticate()
-  }, [searchParams, loginWithTelegramWidget, navigate, isAuthenticated, t])
+    authenticate();
+  }, [searchParams, loginWithTelegramWidget, navigate, isAuthenticated, t]);
 
   if (error) {
     return (
-      <div className="min-h-screen flex items-center justify-center bg-gray-50 py-8 px-4">
-        <div className="max-w-md w-full text-center">
-          <div className="text-red-500 text-5xl mb-4">✗</div>
-          <h2 className="text-lg font-semibold text-gray-900 mb-2">
-            {t('auth.loginFailed')}
-          </h2>
-          <p className="text-sm text-gray-500 mb-6">{error}</p>
-          <button
-            onClick={() => navigate('/login')}
-            className="btn-primary"
-          >
+      <div className="flex min-h-screen items-center justify-center bg-gray-50 px-4 py-8">
+        <div className="w-full max-w-md text-center">
+          <div className="mb-4 text-5xl text-red-500">✗</div>
+          <h2 className="mb-2 text-lg font-semibold text-gray-900">{t('auth.loginFailed')}</h2>
+          <p className="mb-6 text-sm text-gray-500">{error}</p>
+          <button onClick={() => navigate('/login')} className="btn-primary">
             {t('auth.tryAgain')}
           </button>
         </div>
       </div>
-    )
+    );
   }
 
   return (
-    <div className="min-h-screen flex items-center justify-center bg-gray-50">
+    <div className="flex min-h-screen items-center justify-center bg-gray-50">
       <div className="text-center">
-        <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-primary-600 mx-auto mb-4"></div>
-        <h2 className="text-lg font-semibold text-gray-900">
-          {t('auth.authenticating')}
-        </h2>
-        <p className="text-sm text-gray-500 mt-2">{t('common.loading')}</p>
+        <div className="border-primary-600 mx-auto mb-4 h-12 w-12 animate-spin rounded-full border-b-2"></div>
+        <h2 className="text-lg font-semibold text-gray-900">{t('auth.authenticating')}</h2>
+        <p className="mt-2 text-sm text-gray-500">{t('common.loading')}</p>
       </div>
     </div>
-  )
+  );
 }