Split HelpServ into one file per command

REQUEST/CANCEL/LIST/VIEW/TAKE/NEXT/CLOSE each move to their own file;
the oper guard and the shared claim helper stay in lib.rs beside the
dispatcher. No behaviour change.

modules/helpserv/src/close.rs

@@ -0,0 +1,17 @@
+use fedserv_api::{Sender, ServiceCtx, Store};
+
+// CLOSE <id> (aka RESOLVE): resolve a ticket.
+pub fn handle(me: &str, from: &Sender, id: Option<&str>, ctx: &mut ServiceCtx, db: &mut dyn Store) {
+    if !super::require_oper(me, from, ctx) {
+        return;
+    }
+    let Some(n) = id.and_then(|n| n.parse::<u64>().ok()) else {
+        ctx.notice(me, from.uid, "Syntax: CLOSE <id>");
+        return;
+    };
+    if db.help_close(n) {
+        ctx.notice(me, from.uid, format!("Ticket \x02#{n}\x02 closed."));
+    } else {
+        ctx.notice(me, from.uid, format!("Ticket \x02#{n}\x02 isn't open (or doesn't exist)."));
+    }
+}