fix: relay raw IRC bytes instead of re-formatting messages

Preserve original server bytes in IRCMessage.raw and forward those
to clients, avoiding parse/format round-trip that altered messages.

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

src/bouncer/irc.py

@@ -13,6 +13,7 @@ class IRCMessage:
     params: list[str] = field(default_factory=list)
     prefix: str | None = None
     tags: dict[str, str | None] = field(default_factory=dict)
+    raw: bytes | None = None
 
     @property
     def trailing(self) -> str | None:
@@ -78,7 +79,7 @@ def parse(data: bytes) -> IRCMessage:
         command = parts[0].upper()
         params = parts[1:]
 
-    return IRCMessage(command=command, params=params, prefix=prefix, tags=tags)
+    return IRCMessage(command=command, params=params, prefix=prefix, tags=tags, raw=data + b"\r\n")
 
 
 def parse_prefix(prefix: str) -> tuple[str, str | None, str | None]:

src/bouncer/router.py

@@ -104,9 +104,9 @@ class Router:
             if max_msgs > 0:
                 await self.backlog.prune(network_name, keep=max_msgs)
 
-        # Forward to all attached clients
+        # Forward to all attached clients (prefer raw bytes from server)
         clients = self.clients.get(network_name, [])
-        data = msg.format()
+        data = msg.raw if msg.raw else msg.format()
         for client in clients:
             try:
                 client.write(data)