v0.51.345 — Release LI (model override picker for scheduled jobs)

Adds a Model Override dropdown to the Tasks → scheduled-jobs create/edit form (#3809, @b3nw). Populated from /api/models grouped by provider, with Default as the top option; persists model+provider, clears to default, restored on edit/duplicate, disabled in no-agent mode. Surfaces the per-job model override hermes-agent's scheduler already supported (CLI parity). UX-reviewed via screenshots. Includes full ja/de/zh/zh-Hant/ru/fr/pl/it/pt/tr translations for the new strings.