Replace the single scrolling library form dialog with a Plex-style
editor: a left-hand navigation rail with General, Folders, Metadata,
and Advanced panes, inline validation that jumps to the offending
section, a visual icon-card library type picker, and a sticky footer
with Cancel/Save actions.
Form state, provider-chain logic, and save mutations move into a
shared useLibraryForm hook with reusable field-group components, so
the setup wizard keeps its inline layout without duplicating logic.
LibraryPosterSection moves out of AdminLibraries.tsx into its own
component, and the Advanced toggle cards now use semantic theme
tokens instead of hardcoded white overlays that broke light themes.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
