An admin theme's stylesheet was versioned like Filament's assets, by its
package, and Borealis publishes under its old name, which Composer
doesn't know: the address (borealis.css?v=5.10.3.0) only changed with
Filament, so browsers and caches kept an old theme for hours after an
update. It now carries the theme's own release (borealis.css?v=1.0.10).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>