[dotnet-ai] Plugin scaffold + MEAI chat integration

.github/CODEOWNERS

@@ -50,3 +50,6 @@
 /tests/dotnet/dotnet-aot-compat/ @agocke @dotnet/appmodel
 
 /plugins/dotnet/agents/optimizing-dotnet-performance.agent.md @dotnet/appmodel
+
+/plugins/dotnet-ai/ @luisquintanilla @JeremyLikness
+/tests/dotnet-ai/ @luisquintanilla @JeremyLikness

.github/plugin/marketplace.json

@@ -13,6 +13,11 @@
       "name": "dotnet-msbuild",
       "source": "./plugins/dotnet-msbuild",
       "description": "Comprehensive MSBuild and .NET build skills: failure diagnosis, performance optimization, code quality, and modernization."
+    },
+    {
+      "name": "dotnet-ai",
+      "source": "./plugins/dotnet-ai",
+      "description": "AI and ML skills for .NET: technology selection, LLM integration, ML.NET, vector search, RAG, ONNX inference, and agentic workflows."
     }
   ]
-}
+}

plugins/dotnet-ai/plugin.json

@@ -0,0 +1,7 @@
+{
+  "name": "dotnet-ai",
+  "version": "0.1.0",
+  "description": "AI and ML skills for .NET: technology selection, LLM integration, ML.NET, vector search, RAG, ONNX inference, and agentic workflows.",
+  "skills": "./skills/",
+  "agents": "./agents/"
+}