Five builtins (tickets, decisions, git, pql, problems) declared a localized tab title but shipped no catalog and weren't in the hand-kept preload list, so each logged "namespace not registered" on boot. ExtensionManager now loads the i18n namespace of every localized TabContribution when its extension activates — no manual list edit for a new tab — and the five missing en_US catalogs are added. T-155. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>