Sync ratings/comments and refine book UX

backend:

• compute per-book average rating (floored to 1 decimal) and include global_rating/total_comments in book details
• merge reviews with usernames and evaluateId in book review endpoint
• store/update reviews by (user_id, book_id) in both evaluates and comments with validation and response payloads
• add comment to Evaluate model, backfill evaluates from comments, and seed evaluate comments
• change evaluates.note to float for fractional ratings

frontend:

• add review create/update APIs and wire Book view to submit/edit, refresh list, and refresh general rating
• rebuild Book view rating UI with layered stars, tooltip, modal flow, and fractional fills for general/user/comment stars
• prefill user rating when already reviewed; improve comment list header/actions and star sizing
• add BookCard delete confirmation
• EditBook form reworked (categories/writers fetch, writer creation, validation, payload mapping)
• AddBook redirects to new book after create; catalogue updates list after delete; categories empty state