Add ListLibrariesData() method to LibraryHandler to support
server-side rendering of all libraries on the /admin/library page.
This follows the existing pattern of GetUserVisibleLibrariesData() and
GetLibraryTypeData() methods, which return data structures instead of
JSON for template rendering.
Changes:
- Add ListLibrariesData() method (3 lines)
- Returns []database.ListLibrariesRow for template consumption
- Called by frontend route handler for SSR
john-okeefe
3174ec16bc