siteManage i18n namespace missing from 19 of 22 locales
Imported from GitHub issue El-SaMa/oma#104 by @El-SaMa.
Customer-facing bug. The `siteManage` translation namespace (used by `database-users-panel.tsx`, `databases-list-panel.tsx`, and the rest of the service-management panels — including the new Kanta IP-access-control panel) exists in only `en.json`, `fi.json`, and `sv.json`. The other 19 locale files (ar-EG, da, de, es, fr, hi, id, it, ja, nb, nl, pl, pt, ru, tr, uk, zh) are missing it entirely.
Customers on any of those 19 locales see broken strings or English fallback on every service-management page right now.
Fix: backfill the `siteManage` namespace into all 22 locale files (English copy as placeholder is acceptable short-term, but it needs to exist so the key doesn't throw/fallback silently). Expand `i18n-validate.mjs` to enforce strict parity for portal namespaces (currently only enforced for en/fi/sv), not just landing/marketing keys, and wire it into CI.