fix: adapt hallmark codex skill metadata

config/external-sources.json

@@ -11,6 +11,7 @@
       "sparseCheckout": ["skills/hallmark"],
       "webpCompressPaths": ["references/themes"],
       "skillTextReplacements": [
+        {"path": "agents/openai.yaml", "old": "dependencies: []", "new": "dependencies: {}"},
         {"path": "SKILL.md", "old": "<slug>.jpg", "new": "<slug>.webp"},
         {"path": "scripts/theme.mjs", "old": "'.jpg'", "new": "'.webp'"},
         {"path": "scripts/theme.mjs", "old": "${t.slug}.jpg", "new": "${t.slug}.webp"},