Remove spurious BB packet on join and /move

BB is the AO2 bulletin board broadcast — sending it with the background
name displayed "gs4" (or whatever the bg is) as a textbox popup on every
join and room change. Only BN should be sent to set the background.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: SyntaxNyah

src/commands/registry.rs

@@ -230,7 +230,6 @@ pub async fn change_area(session: &mut ClientSession, state: &Arc<ServerState>,
         session.send_packet("HP", &["1", &new_area.def_hp.to_string()]);
         session.send_packet("HP", &["2", &new_area.pro_hp.to_string()]);
         session.send_packet("BN", &[&bg]);
-        session.send_packet("BB", &[&bg]);
 
         let evi = new_area.evidence.clone();
         let evi_refs: Vec<&str> = evi.iter().map(|s| s.as_str()).collect();

src/protocol/handlers.rs

@@ -313,7 +313,6 @@ async fn handle_rd(session: &mut ClientSession, state: &Arc<ServerState>) {
         session.send_packet("HP", &["1", &area.def_hp.to_string()]);
         session.send_packet("HP", &["2", &area.pro_hp.to_string()]);
         session.send_packet("BN", &[&bg]);
-        session.send_packet("BB", &[&bg]);
     }
 
     // Send DONE