feat: add SSE server with agent presence system

- Add SSE transport server for remote MCP connections
- Implement API key authentication
- Add agent presence system (register_agent, list_agents)
- Add list_services tool to discover local services
- Refactor messaging for dynamic agent names

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package-lock.json

@@ -13,6 +13,7 @@
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         "nats": "^2.19.0",
@@ -3228,6 +3229,27 @@
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