REGISTER/DROP/INFO/LIST/ADD/DEL/FLAGS each move to their own file; the
two shared guards (login check, can-manage) stay in lib.rs beside the
dispatcher. No behaviour change.
The service pseudo-clients and the ircd protocol link sat flat at the
repo root, mixed in with the daemon core and the SDK. Move them all
under modules/ so the tree separates concerns cleanly: the daemon in
src/, the SDK every module links against in api/, and the loadable
modules — the pseudo-clients plus the protocol link — in modules/.
Workspace members, the daemon's per-crate dependency paths, and each
module's api path are updated to match; the docs follow. No code change.
