Sync third-party and MCP marketplace plugins

Constraint: Public skills are published only by explicit administrator action unless they are tracked third-party market sources.
Confidence: high
Scope-risk: narrow
Directive: Keep private/internal skills out of the public marketplace and preserve normal incremental market Git history.
Tested: Marketplace validation passed.

plugins/codex/plugins/pdf/THIRD_PARTY_SOURCE.json

@@ -0,0 +1,9 @@
+{
+  "sourceId": "pdf",
+  "repo": "https://github.com/anthropics/skills.git",
+  "ref": "main",
+  "commit": "683bc88e56f3e09ba94f7055977f3d3aa499f202",
+  "adapter": "claude-skill",
+  "sourcePath": "skills/pdf",
+  "syncedAt": "2026-10-06T07:26:41Z"
+}