feat(formulus): add profiles with in-app switching

[Ndacyayisenga-droid]

Summary

• Add profiles with legacy Default migration, profile-owned data and credentials, connection locking, and a Profiles UI.
• Switch A→B→A without restarting: retain one WatermelonDB instance per visited profile, quiesce work, and recover safely from ambiguous registry writes or failed opens. Defer deletion of prepared databases until a real cold start; no WatermelonDB source changes.
• Load one bundled Formplayer on both platforms, guard draft finalization against stale async writes, and warn that profiles are not a security boundary. Only connect to trusted servers and install trusted custom apps.

Validation

• Formulus lint and format check; Jest: 62 suites, 485 tests passed.
• Formplayer lint, format check and production build; Vitest: 37 files, 246 tests passed.
• Android assembleDebug could not run here: NDK 27.0.12077973 is not configured. iOS/on-device validation remains required. Separate public-docs updates are pending in the docs repository.

Manual release checks

1. On Android and iOS, upgrade an install with existing observations/drafts, then create B and switch A→B→A repeatedly without closing the app. Check observation reads/writes, same-URL connections, sync, and custom apps; confirm profile data remains distinct.
2. Delete active and inactive profiles; check the survivor works immediately and deleted data is cleaned up after a real cold launch. Try switching during an open form or active sync and confirm it is blocked safely.
3. On iOS specifically, open the bundled Formplayer and verify photo/audio/video/signature previews and legacy drafts/sticky values offline after switching. The broader WKWebView read grant is not yet device-verified; treat failure as a release blocker.

Profiles organize host data but do not sandbox custom-app code or raw browser storage. Geolocation cache is intentionally global.

[Ndacyayisenga-droid]

Ping Ping @r0ssing

[r0ssing]

Hi @Mishael-2584
Sorry for the quite substantial PR 🥲 - I believe the best way to handle this is if you could test it on a real device and then maybe do a brief AI assisted review of the code changes? Feel free to reach out so we can discuss - let's also include @Ndacyayisenga-droid as he implemented the first parts of this

[r0ssing]

LGTM ;-)