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

@@ -96,8 +96,8 @@
       "repo": "https://github.com/hugohe3/ppt-master.git",
       "ref": "main",
       "adapter": "claude-skill",
-      "commit": "090a133040d9bf41dca887dab78386c553af5dc6",
-      "syncedAt": "2026-08-15T16:00:01Z"
+      "commit": "53c9c2a5e9f1a49096324fba4f95833649c6a0f4",
+      "syncedAt": "2026-08-16T16:00:01Z"
     },
     {
       "id": "grill-me",
@@ -105,8 +105,8 @@
       "repo": "https://github.com/mattpocock/skills.git",
       "ref": "main",
       "adapter": "skill-collection",
-      "commit": "8b78b531ab965735c5dc74f6f7a219e1e37326df",
-      "syncedAt": "2026-08-13T15:59:59Z"
+      "commit": "068b6e0c62393147daf03530149cdce209c93da8",
+      "syncedAt": "2026-08-16T16:00:01Z"
     },
     {
       "id": "next-skills",
@@ -114,8 +114,8 @@
       "repo": "https://github.com/vercel/next.js.git",
       "ref": "canary",
       "adapter": "skill-collection",
-      "commit": "6d0379d4b8558d1157dee78906f0850432453a21",
-      "syncedAt": "2026-08-15T16:00:01Z"
+      "commit": "c18acf5cef6085bdf7561352be4a06acfc43b6fc",
+      "syncedAt": "2026-08-16T16:00:01Z"
     }
   ]
 }