- Add useAppConfigStore (isCloud, isDevMode, tier, contractedClient, inferenceProfile)
- Add GET /api/config/app endpoint to dev-api.py (reads env vars)
- Replace flat /settings route with nested children (9 tabs) + redirect to my-profile
- Add global router.beforeEach guard for system/fine-tune/developer tab access control
- Add SettingsView.vue shell: desktop sidebar with group labels, mobile chip bar, RouterView
- Tab visibility driven reactively by store state (cloud mode hides system, GPU profile gates fine-tune, devMode gates developer)
- Tests: 3 store tests + 3 component tests, all passing