chore: fix stale skill-frontmatter and check-manifests references

c8a7c9e folded the skill-frontmatter hook into skill-size-check but
left validate.sh's FAIL messages, skill-author's create.md, and the
skill template's frontmatter comment naming the deleted hook as the
enforcer -- misleading for anyone tracing a FAIL back to the gate that
raises it.

f11b645 swept check-manifests references but missed a hand-authored
"Local hooks in this repo" table in the git plugin's vendored
pre-commit research doc, which still listed both check-manifests and
skill-frontmatter as active hooks.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YR2CjVumUbEGWcMikcoXBD

plugins/kyberforge/skills/skill-author/assets/templates/SKILL.md

@@ -53,7 +53,7 @@ metadata:
 #     - source-slug-one
 #     - source-slug-two
 # `metadata.version` is REQUIRED on every skill (ADR-0022) and is enforced by the
-# `skill-frontmatter` pre-commit hook. Three-component semver. A newly created
+# `skill-size-check` pre-commit hook. Three-component semver. A newly created
 # skill starts at "0.1.0" — leave the seeded value as it is; "1.0.0" is the seed
 # for a pre-existing skill retrofitted into the rule, not for a new one.
 # The rest of the map is optional: author, category, source_keys.

plugins/kyberforge/skills/skill-author/references/create.md

@@ -99,7 +99,7 @@ boundary-clause form and the length tiers. A hand-invoked skill (`SKILL.md` Step
 plain sentence and `disable-model-invocation: true` instead.
 
 **`metadata.version`** — required on every skill (ADR-0022), not a per-skill or per-plugin choice,
-and enforced by the `skill-frontmatter` pre-commit hook. The scaffold seeds a new skill at
+and enforced by the `skill-size-check` pre-commit hook. The scaffold seeds a new skill at
 `"0.1.0"`; leave that value alone here and let `SKILL.md` Step 4 bump it. (`"1.0.0"` is the seed
 for a pre-existing skill retrofitted into the rule, and never applies to a skill created here.)