Merge step (i): reference sweep — fix stray old-convention refs

Applies triage doc 022. Most of the sweep was no-op because upstream already
renamed everything in place when we branched from origin/main. Remaining
fixes:

- ce-pr-comments-review/SKILL.md: replace compound-engineering:review:/
  workflow: prefixed agent refs with bare ce-<name> form (self-correction
  from step g where I accidentally used old convention)
- ce-essay-edit/SKILL.md: update /essay-outline reference to /ce-essay-outline

Prose references to generic words ("onboarding", "changelog") are left
alone — they are natural-language uses, not skill references.

Known follow-up: tests/review-skill-contract.test.ts and
tests/legacy-cleanup.test.ts still reference locally-removed agents
(ce-dhh-rails-reviewer, ce-kieran-rails-reviewer, ce-data-migration-expert,
ce-security-sentinel). These will need test updates + registration of
removed names in src/utils/legacy-cleanup.ts and
src/data/plugin-legacy-artifacts.ts — flagged for step (j).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

plugins/compound-engineering/skills/ce-essay-edit/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: ce-essay-edit
-description: Expert essay editor that polishes written work through granular line-level editing and structural review. Preserves the author's voice and intent — never softens or genericizes. Pairs with /essay-outline.
+description: Expert essay editor that polishes written work through granular line-level editing and structural review. Preserves the author's voice and intent — never softens or genericizes. Pairs with /ce-essay-outline.
 argument-hint: "[path to essay file, or paste the essay]"
 ---