feat(12-04): setup API client functions + SetupPage wizard component
- Add 7 setup functions to client.ts: fetchSetupStatus, postSetupConfig,
validateSetupDb, validateSetupOidc, validateSetupVapid, postSetupCredential,
postSetupComplete; plus SetupAlreadyLockedError for 423 handling
- Add SetupPage.tsx: standalone 4-step wizard (Welcome → Instance Configuration
→ Calendar Credential → Terminal/Locked) with Surface 2 step indicator,
Surface 5 validation rows, Surface 6 action row, Surface 7 terminal screen,
Surface 8 already-locked screen; role=main, aria-live, no nav shell
- No dangerouslySetInnerHTML; no AppNav/BottomTabBar imports
- All 230 pwa tests pass; typecheck clean; build green
Lucas Berger
62d80f6c46