- Add open_zip_file_dialog command for selecting ZIP files
- Add install_from_zip service method with recursive skill scanning
- Add install_skills_from_zip Tauri command
- Add frontend API methods and useInstallSkillsFromZip hook
- Add "Install from ZIP" button in Skills management page
- Support local skill ID format: local:{directory}
- Add i18n translations for new feature and error messages
- Introduce SSOT (Single Source of Truth) at ~/.cc-switch/skills/
- Add three-app toggle support (Claude/Codex/Gemini) for each skill
- Refactor frontend to use TanStack Query hooks instead of manual state
- Add UnifiedSkillsPanel for managing installed skills with app toggles
- Add useSkills.ts with declarative data fetching hooks
- Extend skills.ts API with unified install/uninstall/toggle methods
- Support importing unmanaged skills from app directories
- Add v2→v3 database migration for new skills table structure