feat: Add eslint

frontend/App.tsx

@@ -16,8 +16,8 @@ function AppContent() {
   useAuthState();
 
   useEffect(() => {
-    hydrateLocale();
-    hydrateTheme();
+    void hydrateLocale();
+    void hydrateTheme();
   }, []);
 
   return <RootNavigator />;

frontend/app.config.ts

@@ -1,4 +1,4 @@
-import { ExpoConfig, ConfigContext } from "expo/config";
+import type { ExpoConfig, ConfigContext } from "expo/config";
 
 export default ({ config }: ConfigContext): ExpoConfig => ({
   ...config,

frontend/eslint.config.js

@@ -0,0 +1,106 @@
+import js from '@eslint/js';
+import tsPlugin from '@typescript-eslint/eslint-plugin';
+import tsParser from '@typescript-eslint/parser';
+import reactPlugin from 'eslint-plugin-react';
+import reactHooksPlugin from 'eslint-plugin-react-hooks';
+import reactNativePlugin from 'eslint-plugin-react-native';
+
+export default [
+  {
+    ignores: [
+      'node_modules/**',
+      '.expo/**',
+      '.expo-shared/**',
+      'dist/**',
+      'build/**',
+      '*.log',
+    ],
+  },
+  js.configs.recommended,
+  // Config files (CommonJS)
+  {
+    files: ['*.config.js', '*.config.ts'],
+    languageOptions: {
+      globals: {
+        require: 'readonly',
+        module: 'readonly',
+        process: 'readonly',
+        __dirname: 'readonly',
+        exports: 'readonly',
+      },
+    },
+  },
+  // TypeScript/React Native files
+  {
+    files: ['**/*.ts', '**/*.tsx'],
+    languageOptions: {
+      parser: tsParser,
+      parserOptions: {
+        ecmaVersion: 2021,
+        sourceType: 'module',
+        ecmaFeatures: {
+          jsx: true,
+        },
+        project: './tsconfig.json',
+        tsconfigRootDir: import.meta.dirname,
+      },
+      globals: {
+        __DEV__: 'readonly',
+        React: 'readonly',
+        JSX: 'readonly',
+        require: 'readonly',
+        module: 'readonly',
+        process: 'readonly',
+        __dirname: 'readonly',
+        atob: 'readonly',
+        btoa: 'readonly',
+      },
+    },
+    plugins: {
+      '@typescript-eslint': tsPlugin,
+      'react': reactPlugin,
+      'react-hooks': reactHooksPlugin,
+      'react-native': reactNativePlugin,
+    },
+    rules: {
+      ...tsPlugin.configs.recommended.rules,
+      ...reactPlugin.configs.recommended.rules,
+      ...reactHooksPlugin.configs.recommended.rules,
+
+      // TypeScript
+      '@typescript-eslint/no-unused-vars': ['error', { argsIgnorePattern: '^_' }],
+      '@typescript-eslint/explicit-module-boundary-types': 'warn',
+      '@typescript-eslint/no-explicit-any': 'error',
+      '@typescript-eslint/consistent-type-imports': ['error', { prefer: 'type-imports' }],
+      '@typescript-eslint/no-require-imports': 'warn',
+      '@typescript-eslint/no-floating-promises': 'error',
+      '@typescript-eslint/await-thenable': 'error',
+      '@typescript-eslint/no-misused-promises': 'error',
+
+      // React
+      'react/react-in-jsx-scope': 'off',
+      'react/prop-types': 'off',
+      'react/display-name': 'off',
+      'react-hooks/rules-of-hooks': 'error',
+      'react-hooks/exhaustive-deps': 'warn',
+
+      // React Native
+      'react-native/no-unused-styles': 'error',
+      'react-native/no-inline-styles': 'warn',
+
+      // General
+      'no-console': ['error', { allow: ['warn', 'error'] }],
+      'prefer-const': 'error',
+      'no-var': 'error',
+      'eqeqeq': ['error', 'always'],
+      'no-implicit-coercion': 'error',
+      'no-return-await': 'error',
+      'require-await': 'error',
+    },
+    settings: {
+      react: {
+        version: 'detect',
+      },
+    },
+  },
+];