Add an isEnglish flag to AUDIBLE_REGIONS and update region handling across the app. UI: populate Audible region selects from AUDIBLE_REGIONS and mark non-English regions with a '*' and an amber warning explaining limited feature support. Service: set axios default param language=english on Audible requests (simplifies/fixes locale handling) and remove the previous locale-correction flow. API: validate regions dynamically from AUDIBLE_REGIONS. Also bump package version to 1.0.2. These changes make region metadata explicit and inform users about limited support for non-English regions while forcing English content where supported.
Introduced a Vitest-based backend unit testing framework with supporting scripts, helpers, and GitHub Actions integration. Refactored the admin settings page to a modular architecture, splitting monolithic logic into feature-specific tabs and hooks for improved maintainability and testability. Updated documentation to reflect the new testing setup and settings architecture, and added new dependencies for testing utilities.