feat(seo-schema-validator): back the upgraded SKILL.md with a working 5-layer pipeline

The "Upgrade Schema Validator" commit added SKILL.md referencing files that did
not exist. Implement them so the skill actually runs:

- scripts/validate_schema.py — 5-layer offline validator (L0 coverage, L1 syntax,
  L2 vocabulary/value-format, L3 rich-result, L4 consistency) with xlsx/csv/jsonl/
  json/dir/live-URL adapters. Gate = zero P0; exits 1 on failure.
- scripts/schema_rules.json — curated hotel-focused, offline rule set (edit-only
  extension point).
- scripts/make_sample.py + fixtures/sample_schema.csv — deliberately flawed fixture
  seeding ≥1 defect per layer; used to self-test.
- references/ — validation-methodology, defect-taxonomy (25 codes), hotel-type-map.
- templates/ — client-qa-report, decision-log.
- code/CLAUDE.md — redirect legacy single-URL tool to the new pipeline.

Noise control: MISSING_RECOMMENDED aggregated one-line-per-node; unexpected-property
checks opt-in via --strict. Generalized client-specific shilla-type-map → hotel-type-map.
Self-tested: default P0=5/P1=4/P2=14 FAIL, --strict --no-recommended P2=0, adapters verified.

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

custom-skills/16-seo-schema-validator/SKILL.md

@@ -42,12 +42,12 @@ This skill's primary job is **Mode A**: catch errors before the client sees them
 
 Full rationale and the type→requirement matrix: `references/validation-methodology.md`.
 Severity + category codes: `references/defect-taxonomy.md`.
-Shilla page-type → schema-type map: `references/shilla-type-map.md`.
+Hotel page-type → schema-type map: `references/hotel-type-map.md`.
 Client-facing report + P1 decision log: `templates/client-qa-report-template.md`, `templates/decision-log.md`.
 
 ## Stage gates (aligned to the project lifecycle 설계→개발→테스트→안정화→런칭 후)
 
-- **G1 설계** — Lock the schema spec and the page-type→type map (`shilla-type-map.md`). Approve the entry template. *DoD:* every page template has an assigned schema type and a required-property list.
+- **G1 설계** — Lock the schema spec and the page-type→type map (`hotel-type-map.md`). Approve the entry template. *DoD:* every page template has an assigned schema type and a required-property list.
 - **G2 개발** — Authors produce entries. Run the validator with `--strict`. *DoD (gate):* **zero P0**, JSON parses for 100% of entries. Entries failing this NEVER reach client review.
 - **G3 테스트** — Re-run; triage P1 in `defect_log.csv` (assign owner/status). Client reviews ONLY the clean, P0-free entries, against a defect report — not raw JSON. *DoD:* P1 triaged, decisions logged in `templates/decision-log.md`.
 - **G4 안정화** — Fix → re-run → confirm no regressions. Spot-check a sample in Google Rich Results Test (online, outside this runtime). *DoD:* P0=0, P1 accepted/closed, online validator green on sample.