fix: format IRC ACTION messages as * nick action * and strip CTCP delimiters

CTCP ACTION messages (/me) were relayed with raw \x01 bytes, rendering
as boxed-X characters in OwnCast. Detect the ACTION pattern, extract the
body, and format it like traditional IRC clients. Also strip \x01 in
irc_format as a safety net for other CTCP leakage.

Made-with: Cursor

src/websocket.rs

@@ -148,6 +148,7 @@ fn parse_ws_message(text: &str) -> Option<BridgeEvent> {
                 username: display_name,
                 body: strip_html(body),
                 id,
+                is_action: false,
             })
         }
         _ => None,