Build a self-contained local reading-list page, index.html, without dependencies.
Users must be able to add a book title, toggle read/unread, and filter All/Unread/Read.
Persist entries and their read state after reload using localStorage.
Reject blank/whitespace-only titles without adding an entry.
Use accessible labels and a clean responsive layout. No network or services.
Reviewer: inspect these requirements and the implementation, report concrete issues
with reproduction steps, do not edit implementation, do not invent bugs.
