feat: initial IRC bouncer implementation

Async Python IRC bouncer with SOCKS5 proxy support, multi-network
connections, password auth, and persistent SQLite backlog with replay.

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

config/bouncer.example.toml

@@ -0,0 +1,29 @@
+[bouncer]
+bind = "127.0.0.1"
+port = 6667
+password = "changeme"
+
+[bouncer.backlog]
+max_messages = 10000
+replay_on_connect = true
+
+[proxy]
+host = "127.0.0.1"
+port = 1080
+
+[networks.libera]
+host = "irc.libera.chat"
+port = 6697
+tls = true
+nick = "mynick"
+user = "mynick"
+realname = "bouncer user"
+channels = ["#test"]
+autojoin = true
+
+# [networks.oftc]
+# host = "irc.oftc.net"
+# port = 6697
+# tls = true
+# nick = "mynick"
+# channels = ["#debian"]