Add beforeNavigate + isDirty tracking to users/[id], users/new,
groups/[id], groups/new, and tags/[id] edit panels. When a user
navigates away with unsaved changes, the navigation is cancelled and
an inline amber warning banner appears with a Discard button that
resumes navigation. Saving successfully clears the dirty flag.
Add i18n key admin_unsaved_warning (de/en/es).
Add spec files for groups/[id] and tags/[id] panels.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
50e637a9f2