Add a dedicated server configuration file (`server.toml`) with clap-based
command line overrides. The server now supports runtime config changes via
terminal commands, and config edits are written back to the TOML file while
preserving comments.
Also let host mode feed the shared network startup through the same server
config resource.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
