First live use of templates/spawn-ui-rename.md on next UI-rename task

templates/spawn-ui-rename.md shipped 2026-06-13 07:29 UTC (task 3b03fd45) as the structural fix for yesterday's PR #12182 scoping failure (3 sub-agent spawns in 50 min to ship one rename). First enforcement pending. When the next UI-rename carry-forward or ad-hoc task appears (next BOLT-1268 sub-PR for cancel/affordance work, or any rename-label-in-an-area task), the spawn prompt MUST cat the literal block from templates/spawn-ui-rename.md. Acceptance: single sub-agent spawn ships the full rename including substrate-grep step + all callsites + shared-helper-promotion + defensive forward-compat + per-callsite tests + filter/tooltip sweep. Also: audit the template's extraction mechanics against the trailer-template structure before first live use. Quick test that the awk literal-block extractor renders the spawn prompt verbatim without the surrounding doc text. Reference: LEARNINGS 2026-06-14 (validation pending streak).