fork: rename to pi-muse-spark, fix pi v0.84 auth check

- Fix false 'not authenticated' warning on pi v0.84+ where authStorage was removed.
  Use canonical ctx.modelRegistry.getProviderAuthStatus() to detect stored/env/runtime keys.
- Fix active model detection for 1.2 and 1.2-contributor.
- Rename package to pi-muse-spark, update homepage/repository to EclipseAditya/pi-muse-spark
- Keep full credit to original https://github.com/seemethere/pi-meta-ai for most of work
- Bump to 0.2.0, update README/CHANGELOG, pi deps to ^0.84.0
- Models: expose 1.2, 1.2-contributor, 1.1

Co-authored-by: seemethere/pi-meta-ai contributors