refactor(agent): consolidate agent type definitions and add multi-agent-type support

packages/server/package.json

@@ -20,6 +20,7 @@
     "@agentclientprotocol/sdk": "^0.4.9",
     "@ai-sdk/openai": "^2.0.52",
     "@boudra/claude-code-acp": "^0.8.5",
+    "@zed-industries/codex-acp": "^0.3.9",
     "@deepgram/sdk": "^3.4.0",
     "@modelcontextprotocol/sdk": "^1.20.1",
     "@openrouter/ai-sdk-provider": "^1.2.0",