feat(rn): [P0] Overview settings

[liuyidi]

Summary

Me hub status overview: current model, connection/runtime, optional version check.

WebUI reference

• webui/src/pages/settings/overview/OverviewSettings.tsx
• webui/src/pages/settings/overview/OverviewPage.tsx

API

• GET /api/settings
• GET /api/settings/version-check (optional / phase 2)

RN landing

• New: src/app/settings/overview.tsx
• Top entry on me.tsx; deep-link to Models / Server

Acceptance

• Shows model + connection status + baseUrl
• Navigate to Models works

Depends

• chore: Settings API thin wrapper
• Ideal after Models settings for deep-link target