Complete the Catalan (ca.po) locale to 100% coverage against en.po,
using es.po as support reference. Adds the 1439 missing entries
across workspace, dashboard, labels, shortcuts, subscription,
errors, modals and onboarding, keeping vosaltres treatment and
IEC/Termcat terminology consistent with the existing strings.
Normalizes placeholders and plural forms, drops the 14 stale
obsolete entries and canonicalizes the file with the repo
translations script.
Closes#11739
AI-assisted-by: muse-spark-1.3-contributor
6954908896