docs: update comprehensive API documentation and project guides
This commit updates all documentation files throughout the project:
- Updated IMPLEMENTATION_PLAN.md with new implementation details
- Updated PROJECT_GUIDELINES.md with coding standards and practices
- Updated README.md with current project information
- Updated SCREENSHOT_AUTOMATION.md with new automation details
- Added TEST_DATA.md with test fixtures data
- Updated cover_image_serving_plan.md with static URL patterns
Documentation API updates:
- Updated API reference documentation for all endpoints including:
- Authentication (login, logout, register, refresh_token)
- Book matching (auto_link, bulk_link, link_book, search)
- Collections (CRUD operations, shelf mappings, auto-assign rules)
- Conflicts (bulk operations, resolve/dismiss)
- Devices (registration, approval, shelf management)
- Highlights (create, update, delete, get)
- Kobo sync (bookmark, markup, initialization, sync)
- KOReader sync (library, metadata, bookmarks, progress)
- Libraries (CRUD, folders, media items, stats)
- Media items (bulk operations, CRUD)
- Notes (CRUD operations)
- OPDS (acquisition, feeds, publication)
- Progress (reading progress tracking)
- Queue (device queue management)
- Ratings (star ratings)
- Scanner (watch mode, scan operations)
- Sync protocols (Kobo, KOReader)
- Users (profile, password, admin operations)
- WebSocket protocols
- Updated user guides (admin, dashboard, settings, sync)
- Updated device setup guides (Kobo, KOReader)
- Updated developer guides (testing, contributing, operations)
- Updated scripts/README.md