Partners translation editor

[seanmalbert]

• General
• Backend
• Public
• Partners

Background / Issue

Jurisdictional admins (not engineers) need to edit translation overrides for their jurisdiction
safely, over a ~1,477-key base, with awareness of fallback, staleness, and section visibility.

Technical Context

• TDD: §6.1, §5.6, §6 (staleness).
• Per-key editor: search matching key paths and values, site labels derived from existing overrides,
  fallback awareness and revert, per-key optimistic-lock conflict UI, interpolation-token-preserving
  validation, the staleness flag, and section-visibility awareness for tIfExists keys (hide via
  empty vs revert via delete; warn on designated visibility keys).
• Depends on: Translation admin CRUD (per-key) #6510; Permission model and flag gating #6512

Acceptance Criteria

• An admin can find a key by searching its value or path, edit it, and save; results show key path,
  value, and site label.
• A stale non-English key shows an "English changed since translated" flag; re-saving clears it.
• A save that drops a %{token} or smart_count structure is blocked with the offending key
  flagged.
• A per-key conflict presents keep-mine / take-theirs; non-conflicting edits are preserved.
• Editing a designated visibility key warns that it will show/hide a section; "hide" (empty) is
  distinct from "revert to base" (delete).

QA Notes

Partners portal (with enableDbDrivenContent on for the test jurisdiction, or as superAdmin).
Exercise search/edit/save, the token-validation block, a two-user conflict on one key, the staleness
flag lifecycle, and the hide-vs-revert distinction with the visibility warning.