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.

config/external-sources.lock.json

@@ -6,8 +6,8 @@
       "repo": "https://github.com/obra/superpowers.git",
       "ref": "main",
       "adapter": "codex-plugin",
-      "commit": "b62616fc12f6a007c6fd5118146821d748da0d33",
-      "syncedAt": "2026-06-17T07:05:29Z"
+      "commit": "896224c4b1879920ab573417e68fd51d2ccc9072",
+      "syncedAt": "2026-06-19T16:00:00Z"
     },
     {
       "id": "oh-my-codex",
@@ -33,8 +33,8 @@
       "repo": "https://github.com/shadcn-ui/ui.git",
       "ref": "main",
       "adapter": "claude-skill",
-      "commit": "c2ddedf5d24e0cee05936c69e1f199a9975a07b2",
-      "syncedAt": "2026-06-18T16:00:00Z"
+      "commit": "3ffd3e1c7c801f5af5aa72f7c70e21ace3b356bc",
+      "syncedAt": "2026-06-19T16:00:00Z"
     },
     {
       "id": "frontend-slides",
@@ -69,8 +69,8 @@
       "repo": "https://github.com/hugohe3/ppt-master.git",
       "ref": "main",
       "adapter": "claude-skill",
-      "commit": "7249902c363f0b33dee9a9f7112fb258ae9c3bf7",
-      "syncedAt": "2026-06-18T16:00:00Z"
+      "commit": "ae6d9096d64d0291933c7a3e6bba2ae4eb533741",
+      "syncedAt": "2026-06-19T16:00:00Z"
     },
     {
       "id": "next-skills",