Attribution system and character detail CRUD

Attribution system - every entity now tracks where its data came from. Sources (wikis, official sites, the work itself) are displayed on public pages and required when curators add or edit data.

Character detail management - curators can now add, edit, and delete physical attributes, traits, abilities, relationships, and life events for characters. Each section supports start/end segment ranges for timeline tracking.

Segment management - drag-and-drop reordering for book segments, with transactional validation to prevent race conditions.

Data provenance - Open Library and ISBNdb identifiers are now stored on authors and books for cross-referencing and duplicate detection.

Group scoping - groups now show which books and series they appear in, with scope badges indicating their context.

Attribution system - every entity now tracks where its data came from. Sources (wikis, official sites, the work itself) are displayed on public pages and required when curators add or edit data.

Segment management - drag-and-drop reordering for book segments, with transactional validation to prevent race conditions.

Data provenance - Open Library and ISBNdb identifiers are now stored on authors and books for cross-referencing and duplicate detection.

Group scoping - groups now show which books and series they appear in, with scope badges indicating their context.