Adds « ‹ [1][2][3][4] › » navigation to the library. Page window
slides to keep the current page in view. Prev/next/first/last controls
are always rendered but disabled at their respective bounds. Also wires
up karmaConfig in angular.json so FirefoxHeadless is used for tests.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
