Re-assert +r when a registered channel is created

fedserv now handles FJOIN (channel create/burst) and sets +r on any
channel that is registered, so a registered channel regains the mode
after it empties and is recreated, and after a services relink. Single
joins arrive as IJOIN and are ignored.

src/engine/mod.rs

@@ -170,6 +170,16 @@ impl Engine {
                 self.network.user_nick_change(&uid, nick);
                 Vec::new()
             }
+            // A registered channel just (re)appeared: re-assert +r. Fires on
+            // creation and on the uplink burst, so registered channels regain the
+            // mode after emptying, and after a services relink.
+            NetEvent::ChannelCreate { channel } => {
+                if self.db.channel(&channel).is_some() {
+                    vec![NetAction::ChannelMode { channel, modes: "+r".to_string() }]
+                } else {
+                    Vec::new()
+                }
+            }
             NetEvent::Quit { uid } => {
                 self.network.user_quit(&uid);
                 self.sasl_sessions.remove(&uid); // drop any half-finished exchange
@@ -938,4 +948,21 @@ mod tests {
         assert!(notice(&out, "dropped"));
         assert!(out.iter().any(|a| matches!(a, NetAction::ChannelMode { channel, modes } if channel == "#room" && modes == "-r")), "drop clears +r: {out:?}");
     }
+
+    // A registered channel (re)appearing re-asserts +r; an unregistered one does not.
+    #[test]
+    fn channel_create_reasserts_registered_mode() {
+        let path = std::env::temp_dir().join("fedserv-chancreate.jsonl");
+        let _ = std::fs::remove_file(&path);
+        let mut db = Db::open(&path, "42S");
+        db.register_channel("#reg", "alice").unwrap();
+        let ns = NickServ { uid: "42SAAAAAA".into(), guest_nick: "Guest".into(), guest_seq: 0 };
+        let mut e = Engine::new(vec![Box::new(ns)], db);
+
+        let out = e.handle(NetEvent::ChannelCreate { channel: "#reg".into() });
+        assert!(out.iter().any(|a| matches!(a, NetAction::ChannelMode { channel, modes } if channel == "#reg" && modes == "+r")), "registered channel regains +r: {out:?}");
+
+        let out = e.handle(NetEvent::ChannelCreate { channel: "#other".into() });
+        assert!(out.is_empty(), "unregistered channel is left alone: {out:?}");
+    }
 }

src/proto/inspircd.rs

@@ -90,6 +90,11 @@ impl Protocol for InspIrcd {
                 }
                 _ => vec![],
             },
+            // FJOIN <chan> <ts> <modes> [params] :<members> — channel create/burst.
+            "FJOIN" => match tokens.next() {
+                Some(chan) if !chan.is_empty() => vec![NetEvent::ChannelCreate { channel: chan.to_string() }],
+                _ => vec![],
+            },
             "QUIT" => vec![NetEvent::Quit { uid: source.unwrap_or_default() }],
             // account-registration relay from an ircd:
             // ACCTREGISTER <reqid> <origin> <kind> <account> <p2> :<p3>
@@ -232,4 +237,14 @@ mod tests {
             "{ev:?}"
         );
     }
+
+    // FJOIN (channel create/burst) surfaces as ChannelCreate for the channel.
+    #[test]
+    fn parses_fjoin_as_channel_create() {
+        let ev = proto().parse(":0IR FJOIN #chan 1783845132 +tn :o,0IRAAAAAB:0");
+        assert!(
+            matches!(ev.as_slice(), [NetEvent::ChannelCreate { channel }] if channel == "#chan"),
+            "{ev:?}"
+        );
+    }
 }

src/proto/mod.rs

@@ -12,6 +12,9 @@ pub enum NetEvent {
     Privmsg { from: String, to: String, text: String },
     UserConnect { uid: String, nick: String },
     NickChange { uid: String, nick: String },
+    // A channel was created or bursted (InspIRCd FJOIN). Subsequent single joins
+    // arrive as IJOIN and are not surfaced.
+    ChannelCreate { channel: String },
     Quit { uid: String },
     // An ircd relaying an IRCv3 account-registration request to us as the authority.
     AccountRequest { reqid: String, origin: String, kind: String, account: String, p2: String, p3: String },