chore: export decode_message and encode_message from top-level package

The convenience functions decode_message() and encode_message() are now
importable directly from dqlitewire, matching the existing exports of
MessageDecoder and MessageEncoder.

Closes #107

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqlitewire/__init__.py

@@ -41,7 +41,7 @@
     )
 
 from dqlitewire.buffer import ReadBuffer, WriteBuffer
-from dqlitewire.codec import MessageDecoder, MessageEncoder
+from dqlitewire.codec import MessageDecoder, MessageEncoder, decode_message, encode_message
 from dqlitewire.constants import (
     PROTOCOL_VERSION,
     PROTOCOL_VERSION_LEGACY,
@@ -72,6 +72,8 @@
     "ResponseType",
     "ValueType",
     "WriteBuffer",
+    "decode_message",
+    "encode_message",
 ]
 
 __version__ = "0.1.0"