Introduce a complete admin System Logs feature: adds frontend components (filters, date picker, active filter chips, rows, detail panel, skeletons, pagination, toolbar, user typeahead, and styles) under src/app/admin/logs/components, plus hooks (useAutoRefreshControl, useLogsUrlState, useUserSearch) and types. Add constants for job labels and log filters, wire URL-driven filters/search/date-range/hasError/user/audiobookQuery with pause-on-interact behavior and page-size options. Update API route (/api/admin/logs) to support the expanded query params and exported where-builder. Update documentation (TABLEOFCONTENTS and admin-dashboard) and add/adjust tests for the new admin logs UI and API behavior.
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.