Client: Narrow down the fields fetched for book lists

[ilsea]

On client side:
The type in book.ts lists all fields needed across entire app.
The Browse and MyShelf pages render BookGrid with BookCard and do not need all this info, only a subsection
The BookDetail page uses all fields

For now, the same book type is passed around everywhere.
For later: Narrow down the fields used for BookCard (..grid, browse, shelf) to only the necessary ones, to avoid fetching loads more data than needed. At the same time: make sure fetch asks for the same exact fields to ensure results match what's expected.

To do

• Add BookSummary = Pick<Book, "id" | "title" | "authors" | "coverURL" | "publishedYear"> in types/book.ts.
• Use BookSummary in BookCard, BookGrid and the list queries on Browse and My shelf.
• Update the GraphQL list queries to request exactly the BookSummary fields, and nothing else.
• Keep the full Book type (and query) for the BookDetail page.
• Change the query and the type in the same commit, so they can't drift apart. TypeScript can't check GraphQL results, so a mismatch shows up only at runtime.