Clippy sweep: clean across the workspace

- Box the oversized enum variants (Event::AccountRegistered, gossip
  Msg::Entry) so small events aren't sized to a full Account; serde is
  transparent so the wire/log format is unchanged.
- Use the configured server description in the SERVER line (it was
  hardcoded and the config field went unread).
- Derive the ChanServ SET label from the ChanSetting (drops toggle's 8th
  arg); rename inspircd from_us -> sourced.
- allow the two framework-idiom lints with rationale (tonic's Status in
  authorize; the guest-rename handler's inherent arg count).
- Auto-fixed map_or/contains/split_once style lints.

nickserv/src/ghost.rs

@@ -4,6 +4,9 @@ use fedserv_api::NetView;
 
 // GHOST/RECOVER <nick> [password]: rename off a session using a nick you own,
 // either by being identified to its account or giving that account's password.
+// Every argument is a distinct input the guest-rename needs (the guest nick and
+// its sequence counter among them), so the count is inherent.
+#[allow(clippy::too_many_arguments)]
 pub fn handle(me: &str, guest_nick: &str, guest_seq: &mut u32, from: &Sender, args: &[&str], ctx: &mut ServiceCtx, net: &dyn NetView, db: &dyn Store) {
     let Some(&target) = args.get(1) else {
         ctx.notice(me, from.uid, "Syntax: GHOST <nick> [password]");