feat: add quota check and account management to auth login

- Add enabled field to AccountMetadataV3 for account enable/disable
- Add getEnabledAccounts/getTotalAccountCount methods to AccountManager
- Add quota.ts with quota checking logic via fetchAvailableModels API
- Integrate 'Check quotas' and 'Manage accounts' options into auth menu
- Display quota status for Claude, Gemini 3 Pro, and Gemini 3 Flash
- Add standalone check-quota.mjs script for manual verification
- Update tsconfig to exclude temp_research folder