### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

In an Enterprise Control Plane / Data Plane split deployment, the CP Admin UI renders a full MCP Servers section with "Create MCP Server" button. However:

1. Clicking "Create MCP Server" always fails with: Error creating MCP Server: LLM API routes are disabled for this instance 2. The MCP Servers list in the UI is always empty, even though servers exist in the shared database (registered successfully via the DP API) 3. Update and delete operations are similarly blocked

**Root cause:** all /v1/mcp/server* routes are classified as LLM API routes, so they are blocked on the CP by DISABLE_LLM_API_ENDPOINTS: "true". MCP server management is an admin operation (requires master key, no inference traffic involved) and should be governed by DISABLE_ADMIN_ENDPOINTS instead — consistent with /v1/model, /v1/key, /v1/team etc.

### Steps to Reproduce

1. Deploy Enterprise LiteLLM with CP/DP split 2. Set DISABLE_LLM_API_ENDPOINTS: "true" on Control Plane (standard enterprise config) 3. Open the CP Admin UI → navigate to MCP Servers 4. Observe: list is empt…