Prepare LicenseKit 2.0.0

[naviapis]

Summary

• prepare the breaking LicenseKit 2.0.0 API and release metadata
• make provider, activation, validation, refresh, and persistence contracts explicit and typed
• split activation persistence from opaque state metadata persistence
• harden restoration, grace-period, cleanup-failure, and concurrent refresh behavior
• align package documentation, CI, formatting, and contribution metadata with sibling packages

Impact

This is a breaking release. Consumers must migrate renamed identifiers, failable value construction, provider error contracts, and the new activation/state-metadata persistence split described in CHANGELOG.md.

Validation

• make check
• 193 tests, 0 failures
• Debug and Release builds with strict concurrency and warnings as errors
• swift package diagnose-api-breaking-changes v1.2.0 confirms the expected breaking surface
• Release builds previously validated for macOS, iOS, tvOS, watchOS, and visionOS