Chat Modes -> Agents (#433)

* Migrating chat modes to agents now that's been released to stable

* Fixing collections

* Fixing names of agents

* Formatting

* name too long

* Escaping C# agent name

collections/python-mcp-development.collection.yml

@@ -7,8 +7,8 @@ items:
     kind: instruction
   - path: prompts/python-mcp-server-generator.prompt.md
     kind: prompt
-  - path: chatmodes/python-mcp-expert.chatmode.md
-    kind: chat-mode
+  - path: agents/python-mcp-expert.agent.md
+    kind: agent
     usage: |
       recommended