feat(rn): [P1] Security / access mode settings

[liuyidi]

Summary

Security/Advanced: local service access + Default Permission vs Full Access.

WebUI reference

• webui/src/pages/settings/advanced/AdvancedSettings.tsx
• webui/src/pages/settings/advanced/useAdvancedSettings.ts

API

• …/network-safety/update and access-mode related updates

RN landing

• New: src/app/settings/advanced.tsx (or security.tsx)

Acceptance

• Toggle Default Permission vs Full Access
• Copy explains restart requirement if needed

Depends

• chore: Settings API thin wrapper