fix: resolve all 14 ESLint warnings across the codebase

- Add varsIgnorePattern to no-unused-vars for destructuring patterns
- Fix all react-hooks/exhaustive-deps by adding missing dependencies
- Refactor useAnimatedNumber to use ref instead of stale state closure
- Wrap handleLinkResult in useCallback for stable deps
- Extract OAuth utilities from OAuthCallback.tsx to utils/oauth.ts
- Extract background config utilities to utils/backgroundConfig.ts
- Remove unused catch parameter in GiftSubscription

eslint.config.js

@@ -30,7 +30,10 @@ export default tseslint.config(
       'react-hooks/variables': 'off',
       'react-refresh/only-export-components': ['warn', { allowConstantExport: true }],
       '@typescript-eslint/no-explicit-any': 'warn',
-      '@typescript-eslint/no-unused-vars': ['warn', { argsIgnorePattern: '^_' }],
+      '@typescript-eslint/no-unused-vars': [
+        'warn',
+        { argsIgnorePattern: '^_', varsIgnorePattern: '^_', destructuredArrayIgnorePattern: '^_' },
+      ],
       'no-empty': ['warn', { allowEmptyCatch: true }],
       'no-eval': 'error',
       'no-implied-eval': 'error',