modules: split services and the ircd link into external crates

nickserv, chanserv and the InspIRCd protocol move out of the binary into their
own workspace crates (fedserv-nickserv, fedserv-chanserv, fedserv-inspircd),
each depending only on fedserv-api. human_time and the branded account emails
move into the SDK crate so a module needs nothing from core; the engine keeps
its own inherent methods and builds emails via fedserv-api too. The bin now
constructs each module from its crate instead of an in-tree #[path] include.
Proves the SDK is self-sufficient: a third-party module is the same shape.

nickserv/src/lib.rs

@@ -0,0 +1,78 @@
+use fedserv_api::Store;
+use fedserv_api::{Sender, Service, ServiceCtx};
+use fedserv_api::NetView;
+
+#[path = "register.rs"]
+mod register;
+#[path = "identify.rs"]
+mod identify;
+#[path = "logout.rs"]
+mod logout;
+#[path = "cert.rs"]
+mod cert;
+#[path = "info.rs"]
+mod info;
+#[path = "alist.rs"]
+mod alist;
+#[path = "set.rs"]
+mod set;
+#[path = "drop.rs"]
+mod drop;
+#[path = "group.rs"]
+mod group;
+#[path = "glist.rs"]
+mod glist;
+#[path = "ungroup.rs"]
+mod ungroup;
+#[path = "ghost.rs"]
+mod ghost;
+#[path = "resetpass.rs"]
+mod resetpass;
+#[path = "confirm.rs"]
+mod confirm;
+
+pub struct NickServ {
+    pub uid: String,
+    // Nick prefix assigned on LOGOUT (default "Guest"); a per-session sequence is
+    // appended so successive guests don't collide within a run.
+    pub guest_nick: String,
+    pub guest_seq: u32,
+}
+
+impl Service for NickServ {
+    fn nick(&self) -> &str {
+        "NickServ"
+    }
+    fn uid(&self) -> &str {
+        &self.uid
+    }
+    fn gecos(&self) -> &str {
+        "Nickname Services"
+    }
+    fn manages_accounts(&self) -> bool {
+        true
+    }
+
+    fn on_command(&mut self, from: &Sender, args: &[&str], ctx: &mut ServiceCtx, net: &dyn NetView, db: &mut dyn Store) {
+        let me = self.uid.as_str();
+        match args.first().map(|s| s.to_ascii_uppercase()).as_deref() {
+            Some("REGISTER") => register::handle(me, from, args, ctx),
+            Some("IDENTIFY") | Some("ID") => identify::handle(me, from, args, ctx, db),
+            Some("LOGOUT") | Some("LOGOFF") => logout::handle(me, &self.guest_nick, &mut self.guest_seq, from, ctx),
+            Some("CERT") => cert::handle(me, from, args, ctx, db),
+            Some("INFO") => info::handle(me, from, args, ctx, db),
+            Some("ALIST") => alist::handle(me, from, ctx, db),
+            Some("SET") => set::handle(me, from, args, ctx, db),
+            Some("DROP") => drop::handle(me, from, args, ctx, net, db),
+            Some("GROUP") => group::handle(me, from, args, ctx, db),
+            Some("GLIST") => glist::handle(me, from, ctx, db),
+            Some("UNGROUP") => ungroup::handle(me, from, args, ctx, db),
+            Some("GHOST") | Some("RECOVER") => ghost::handle(me, &self.guest_nick, &mut self.guest_seq, from, args, ctx, net, db),
+            Some("RESETPASS") => resetpass::handle(me, from, args, ctx, db),
+            Some("CONFIRM") => confirm::handle(me, from, args, ctx, db),
+            Some("HELP") => ctx.notice(me, from.uid, "NickServ looks after your nickname. Commands: \x02REGISTER\x02 <password> [email], \x02IDENTIFY\x02 [account] <password>, \x02INFO\x02 [account], \x02ALIST\x02, \x02GROUP\x02/\x02GLIST\x02/\x02UNGROUP\x02, \x02GHOST\x02 <nick> [password], \x02SET\x02 PASSWORD|EMAIL, \x02RESETPASS\x02 <account>, \x02CONFIRM\x02 <code>, \x02DROP\x02 <password>, \x02LOGOUT\x02, \x02CERT\x02 ADD|DEL|LIST <password> [fingerprint]."),
+            Some(other) => ctx.notice(me, from.uid, format!("I don't know the command \x02{other}\x02. Try \x02HELP\x02.")),
+            None => {}
+        }
+    }
+}