Config generator from synapse seems to die for local auth config

[grinapo]

Describe the bug

$ mas-cli config generate --synapse-config /tmp/homeserver.yaml
…
2026-01-15T16:54:15.100167Z  INFO mas_cli::commands::config:106 Adjusting MAS config to match Synapse config from ["/tmp/homeserver.yaml"]
Error: invalid type: found unit, expected struct EnableableSection for key "default.cas_config" in /tmp/homeserver.yaml YAML file

There is no cas_config, it's the default (empty) section in the conffile:

cas_config:
  # nothing at all