- Remove disabled state from series name input in edit modal
- Add duplicate name validation in SeriesController (resolves TODO)
- Update nameIgnorePrefix when series name changes
- Add frontend validation for duplicate series names
- Add updateSeriesName method to PATCH series immediately on rename
- Show backend error message in toast on failure
- Add i18n string for duplicate name error message
This enables users to rename existing series while preventing duplicate
series names within the same library.