chore: update translations from Globalization Pipeline (#14184)

* chore: update translations from Globalization Pipeline

Syncs all frontend and backend locale files (de, es, fr, ja, pt, zh-Hans)
with the latest strings from IBM Globalization Pipeline. Includes the 72
agentTab.* keys added in the A2A feature (#13831) that were never uploaded
to GP before — the upload workflow's job condition was broken so those keys
were never submitted for translation until now.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* [autofix.ci] apply automated fixes

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Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: 3 people