feat(skill-quality): enforce frontmatter name matches skill directory name

[kyle-sexton]

Problem

docs/PLUGIN-PHILOSOPHY.md:69 mandates it:

The frontmatter name always matches the skill directory name, in the character set the Agent Skills specification allows.

Nothing enforces it. Check 1 in plugins/skill-quality/scripts/check-skill.sh asserts only that name: is present and non-empty:

grep -qE '^name:[[:space:]]*\S' <<<"$FRONTMATTER" || err "frontmatter missing 'name:'"

A mismatch is not cosmetic. The directory name is what Claude Code namespaces the skill by, so a divergent frontmatter name silently changes the invocation the doctrine says the skill has — and the picker labels rows by the resolved leaf name, so the drift is invisible in the listing too.

Scope

Extend check 1 with a deterministic FAIL when frontmatter name differs from the containing directory name.

Current conformance

Verified across the whole catalog before proposing this as blocking:

checked 143; name!=dir violations: 0

So the gate lands green on today's tree — no baseline file, no grandfathering needed.

Related

• Refs docs(naming): namespacing guarantees invocation uniqueness, not picker display uniqueness #710 — the doctrine clarification that surfaced this hole.