Add awesome-skills plugin: 856+ skill router via antigravity-awesome-skills

9 category-based router skills (architecture, business, data-ai, development,
general, infrastructure, security, testing, workflow) that auto-invoke on
matching keywords and route to the appropriate antigravity skill file.

Includes generate-indexes.py script to regenerate category indexes from
catalog.json when the antigravity repo updates.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -25,6 +25,15 @@
       "author": {
         "name": "ki-brain"
       }
+    },
+    {
+      "name": "awesome-skills",
+      "source": "./awesome-skills",
+      "description": "856+ expert skills router for architecture, development, AI, security, testing, infrastructure, business, and workflow (powered by antigravity-awesome-skills)",
+      "version": "1.0.0",
+      "author": {
+        "name": "ki-brain"
+      }
     }
   ]
 }