Docs mismatch: Entra ServiceAccount example uses unsupported auth combination

[shreypachauri3]

Summary

The section With ServiceAccount Credentials in docs/ENTRA_ID_SETUP.md currently shows:

• require_oauth = true
• cluster_auth_mode = kubeconfig

This combination is rejected by the server at startup.

Actual Behavior

Server startup fails with:

cluster_auth_mode "kubeconfig" is not compatible with require_oauth=true: all authenticated users would share a single cluster identity, breaking per-user audit trails; use passthrough or token exchange to preserve user identity on the cluster

Notes

The runtime behavior is expected, but the documentation should clearly mention this constraint to avoid confusion.

Reproduction Steps

1. Configure the server exactly as shown in docs/ENTRA_ID_SETUP.md.
2. Start kubernetes-mcp-server with that configuration.
3. Observe startup failure with the incompatibility error above.