NickServ GETEMAIL + ChanServ SET RESTRICTED

GETEMAIL (auspex) lists accounts whose email matches a glob. SET
RESTRICTED makes a channel kick anyone without access (or oper) as they
join, mirroring the SECUREOPS on-join enforcement.

modules/nickserv/src/getemail.rs

@@ -0,0 +1,19 @@
+use echo_api::{Priv, Sender, ServiceCtx, Store};
+
+// GETEMAIL <email>: list accounts registered with a matching email. Oper-only.
+pub fn handle(me: &str, from: &Sender, args: &[&str], ctx: &mut ServiceCtx, db: &dyn Store) {
+    if !from.privs.has(Priv::Auspex) {
+        ctx.notice(me, from.uid, "Access denied — GETEMAIL needs the \x02auspex\x02 privilege.");
+        return;
+    }
+    let Some(&pattern) = args.get(1) else {
+        ctx.notice(me, from.uid, "Syntax: GETEMAIL <email>");
+        return;
+    };
+    let accounts = db.accounts_by_email(pattern);
+    if accounts.is_empty() {
+        ctx.notice(me, from.uid, format!("No accounts use an email matching \x02{pattern}\x02."));
+        return;
+    }
+    ctx.notice(me, from.uid, format!("Accounts with email matching \x02{pattern}\x02: {}", accounts.join(", ")));
+}