refactor(handlers): Phase 2 - create MediaHandler with CRUD operations
- Add worker field to MediaHandler struct
- Make NewMediaHandler accept optional worker parameter
- Move 24 media CRUD methods from ebook.go to MediaHandler:
* Media CRUD: ListMediaItems, GetMediaItem, ListMediaItemsFiltered, CreateMediaItem, UpdateMediaItem, DeleteMediaItem, SearchMediaItems
* Ratings: CreateMediaRating, GetMediaRating, UpdateMediaRating, DeleteMediaRating
* Progress: GetMediaReadingProgress, UpdateMediaReadingProgress, DeleteMediaReadingProgress
* Notes: GetMediaNotes, CreateMediaNote, GetMediaNote, UpdateMediaNote, DeleteMediaNote
* Highlights: GetMediaHighlights, CreateMediaHighlight, GetMediaHighlight, UpdateMediaHighlight, DeleteMediaHighlight
Methods are copied (not moved) to maintain backward compatibility during refactoring.
Duplicates will be removed in Phase 7.
This is Phase 2 of the ebook.go refactoring plan.