siteManage i18n namespace missing from 19 of 22 locales
Imported from GitHub issue [El-SaMa/oma#104](https://github.com/El-SaMa/oma/issues/104) by @El-SaMa.
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**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.