Store pinned library IDs on the user record and expose GET/PUT
/me/pinned-libraries endpoints. The web client now loads and saves pins
through the API, migrates legacy localStorage data once, and applies
pinned ordering on both the libraries and home pages.
Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: truewhile <truewhile@users.noreply.github.com>