fix: auth UX follow-up polish and quota reliability

[iam-brain]

Summary:

• remove remaining legacy non-TTY login prompt flow from runtime auth path
• always route TTY opencode auth login through the interactive auth menu when accounts exist
• fix Check quotas in auth menu to refresh expired tokens before quota fetch and continue on per-account failures
• show account plan in menu labels (user@example.com (Plus)) style quota report with ANSI chrome and Unicode layout

Verification:

• npm run typecheck\n- npx vitest run test/auth-login-workflow.test.ts test/plugin-loader.test.ts test/codex-quota-report.test.ts