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

@@ -60,8 +60,8 @@
       "repo": "https://github.com/shadcn-ui/ui.git",
       "ref": "main",
       "adapter": "claude-skill",
-      "commit": "4baadbc6517070ae8f8feb2c97037adc2b305544",
-      "syncedAt": "2026-07-24T06:18:20Z"
+      "commit": "7774cd7dcee1e98d0815aa6e829f33a7fc952fdf",
+      "syncedAt": "2026-07-27T03:11:20Z"
     },
     {
       "id": "frontend-slides",
@@ -96,8 +96,8 @@
       "repo": "https://github.com/hugohe3/ppt-master.git",
       "ref": "main",
       "adapter": "claude-skill",
-      "commit": "1912f0112c711e7b46d893a461648c4cde437314",
-      "syncedAt": "2026-07-24T16:00:00Z"
+      "commit": "de0af38a07706eee03b97f6186d8e0ffba595892",
+      "syncedAt": "2026-07-27T03:11:20Z"
     },
     {
       "id": "next-skills",
@@ -105,8 +105,8 @@
       "repo": "https://github.com/vercel/next.js.git",
       "ref": "canary",
       "adapter": "skill-collection",
-      "commit": "6fd889b922fc0aaeaa7a6b63fce5450e20d2df99",
-      "syncedAt": "2026-07-24T16:00:00Z"
+      "commit": "3f2cf7e1a024ab0b5a0ee16e02f0a258173947ae",
+      "syncedAt": "2026-07-27T03:11:20Z"
     }
   ]
 }