v0.1.0 of feature_flags_toggly_isar

Isar database persistence backend for the Toggly Flutter SDK (feature_flags_toggly), enabling offline feature flag, variant, and JWKS caching. Changelog excerpt: 2026-05-30 ### Added - Initial release. IsarCacheProvider, a TogglyCacheProviderbacked by the Isar database, persisting feature flags, variant definitions, and JWKS for offline restart with feature_flags_toggly.