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": "6fd4507659784c351abbd2bc264c7162cfd386dc",
-      "syncedAt": "2026-06-10T07:28:13Z"
+      "commit": "8cf39006140a743dce31ba4046fceab90cc214e6",
+      "syncedAt": "2026-06-16T16:00:00Z"
     },
     {
       "id": "oh-my-codex",
@@ -33,8 +33,8 @@
       "repo": "https://github.com/shadcn-ui/ui.git",
       "ref": "main",
       "adapter": "claude-skill",
-      "commit": "9197676b3d09b77f51b17b63e5978db29e498ca4",
-      "syncedAt": "2026-06-15T15:59:59Z"
+      "commit": "6ec117715f8519326f0ae8c9984b930f313bdb71",
+      "syncedAt": "2026-06-16T16:00:00Z"
     },
     {
       "id": "frontend-slides",
@@ -69,8 +69,8 @@
       "repo": "https://github.com/hugohe3/ppt-master.git",
       "ref": "main",
       "adapter": "claude-skill",
-      "commit": "45d9a79874d8700583feb60ddfbca46df437864b",
-      "syncedAt": "2026-06-15T15:59:59Z"
+      "commit": "886c159db5bfb693ab8b228b03a1ace75aacd630",
+      "syncedAt": "2026-06-16T16:00:00Z"
     },
     {
       "id": "next-skills",