Add a "Find book details online" section to the Edit modal: search Google Books + OpenLibrary and pick a record to fill title, authors, and description (and apply its cover). Companion to the existing cover search, independent of the enrichment config. New `upload/metadata_search.rs` returns multiple candidate records; served via GET /api/books/{id}/meta/search. Google Books descriptions are HTML- stripped to plain text. Picking a record only fills the form fields (cover applies immediately); the user reviews and clicks Save.