NickServ: add UPDATE and LIST

UPDATE re-applies your auto-joins and vhost and re-checks for waiting
memos without re-identifying. LIST (auspex-gated) shows registered
accounts matching a glob, capped at 100. Adds an accounts_matching store
method.

modules/nickserv/src/list.rs

@@ -0,0 +1,23 @@
+use echo_api::{human_time, Priv, Sender, ServiceCtx, Store};
+
+// A cap so a broad glob can't flood the requesting oper.
+const MAX_SHOWN: usize = 100;
+
+// LIST <pattern>: list registered accounts matching a glob. 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 — LIST needs the \x02auspex\x02 privilege.");
+        return;
+    }
+    let pattern = args.get(1).copied().unwrap_or("*");
+    let mut matches = db.accounts_matching(pattern);
+    matches.sort_by_key(|a| a.name.to_ascii_lowercase());
+
+    ctx.notice(me, from.uid, format!("Accounts matching \x02{pattern}\x02:"));
+    for a in matches.iter().take(MAX_SHOWN) {
+        let flag = if a.verified { "" } else { " (unconfirmed)" };
+        ctx.notice(me, from.uid, format!("  \x02{}\x02  registered {}{}", a.name, human_time(a.ts), flag));
+    }
+    let more = if matches.len() > MAX_SHOWN { format!(", showing the first {MAX_SHOWN}") } else { String::new() };
+    ctx.notice(me, from.uid, format!("End of list — {} match(es){more}.", matches.len()));
+}