Publish third-party presentation skills

Add frontend-slides, guizang-ppt-skill, html-ppt, and ppt-master as public third-party marketplace sources with localized Chinese metadata, provenance locks, and generated Codex plugin directories. The sync script now handles root-directory skills without VCS/cache artifacts and supports sparse checkout for large upstream repositories.

Constraint: Third-party plugin content is generated from config/external-sources.json and locked to the upstream commit recorded in external-sources.lock.json.
Rejected: Keeping administrator-added local copies | Stable third-party sources give clearer provenance and let KeyInfo replace duplicates consistently.
Confidence: high
Scope-risk: moderate
Directive: Re-run external source sync instead of manually editing generated plugin directories; keep ppt-master sparseCheckout scoped unless the upstream skill layout changes.
Tested: python scripts/validate_marketplace.py; python /Users/eapil/.codex/skills/.system/plugin-creator/scripts/validate_plugin.py plugins/codex/plugins/frontend-slides; python /Users/eapil/.codex/skills/.system/plugin-creator/scripts/validate_plugin.py plugins/codex/plugins/guizang-ppt-skill; python /Users/eapil/.codex/skills/.system/plugin-creator/scripts/validate_plugin.py plugins/codex/plugins/html-ppt; python /Users/eapil/.codex/skills/.system/plugin-creator/scripts/validate_plugin.py plugins/codex/plugins/ppt-master; git diff --check.
Not-tested: Codex marketplace install/remove smoke test and PowerShell sync execution were not run; pwsh/powershell is unavailable on this machine.

config/external-sources.lock.json

@@ -26,6 +26,42 @@
       "adapter": "claude-skill",
       "commit": "1994caba0b2140d4d5aa765bb9d7d4412d6aaabb",
       "syncedAt": "2026-06-11T02:45:51Z"
+    },
+    {
+      "id": "frontend-slides",
+      "pluginName": "frontend-slides",
+      "repo": "https://github.com/zarazhangrui/frontend-slides.git",
+      "ref": "main",
+      "adapter": "claude-skill",
+      "commit": "871ce4daa13599d6195fe0bb465eb0ed80b2fa44",
+      "syncedAt": "2026-06-11T03:57:53Z"
+    },
+    {
+      "id": "guizang-ppt-skill",
+      "pluginName": "guizang-ppt-skill",
+      "repo": "https://github.com/op7418/guizang-ppt-skill.git",
+      "ref": "main",
+      "adapter": "claude-skill",
+      "commit": "82fe5ae129e8c2a12e1155fcabed6703342749d6",
+      "syncedAt": "2026-06-11T03:57:53Z"
+    },
+    {
+      "id": "html-ppt",
+      "pluginName": "html-ppt",
+      "repo": "https://github.com/lewislulu/html-ppt-skill.git",
+      "ref": "main",
+      "adapter": "claude-skill",
+      "commit": "f3a8435d3901697d5ac5e64d356c933637e43107",
+      "syncedAt": "2026-06-11T03:57:53Z"
+    },
+    {
+      "id": "ppt-master",
+      "pluginName": "ppt-master",
+      "repo": "https://github.com/hugohe3/ppt-master.git",
+      "ref": "main",
+      "adapter": "claude-skill",
+      "commit": "2b337bec18c2cb1381fee2dfca2e6f6fed463ce6",
+      "syncedAt": "2026-06-11T03:57:53Z"
     }
   ]
 }