A [modules] block selects which services start (default: NickServ + ChanServ);
main.rs constructs each compiled-in module only when named, so a node can run a
subset and optional modules ship dormant. Add fedserv-example, a minimal
read-only Service that depends on fedserv-api alone -- the template a new
pseudo-client is copied from, enabled by adding "example" to the config.
MODULES.md documents writing and registering a service or protocol module.
