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/glist.rs

@@ -0,0 +1,17 @@
+use fedserv_api::Store;
+use fedserv_api::{Sender, ServiceCtx};
+
+// GLIST: list the nicks grouped to your account.
+pub fn handle(me: &str, from: &Sender, ctx: &mut ServiceCtx, db: &dyn Store) {
+    let Some(account) = from.account else {
+        ctx.notice(me, from.uid, "You need to be logged in. Identify to NickServ first.");
+        return;
+    };
+    let mut nicks = db.grouped_nicks(account);
+    nicks.sort();
+    ctx.notice(me, from.uid, format!("Nicks grouped to \x02{account}\x02:"));
+    ctx.notice(me, from.uid, format!("  \x02{account}\x02 (main)"));
+    for n in nicks {
+        ctx.notice(me, from.uid, format!("  \x02{n}\x02"));
+    }
+}