feat(platform): add Forward message support for aiocqhttp adapter (#2003)

* feat(platform): add Forward message support for aiocqhttp adapter

- Add _send_forward_message method to send merged forward cards via OneBot API
- Support NapCat's send_forward_msg API with fallback to send_group_forward_msg
- Fix MessageChain deserialization for Forward messages in handler.py
- Properly deserialize nested ForwardMessageNode.message_chain to preserve data

This enables plugins to send QQ merged forward cards through the standard
LangBot send_message API using the Forward message component.

* style: fix ruff lint and format issues

- Remove f-string prefix from log message without placeholders
- Apply ruff format to aiocqhttp.py and handler.py

* refactor: remove custom deserializer, rely on SDK for Forward deserialization

- Remove _deserialize_message_chain from handler.py; use standard
  MessageChain.model_validate() (Forward handling fixed in SDK via
  langbot-app/langbot-plugin-sdk#38)
- Fix group_id type: use int instead of str for OneBot compatibility
- Add warning log when Forward message is used with non-group target

* chore: bump langbot-plugin to 0.2.7 (Forward deserialization fix)

---------

Co-authored-by: RockChinQ <rockchinq@gmail.com>

pyproject.toml

@@ -64,7 +64,7 @@ dependencies = [
     "chromadb>=0.4.24",
     "qdrant-client (>=1.15.1,<2.0.0)",
     "pyseekdb==1.0.0b7",
-    "langbot-plugin==0.2.6",
+    "langbot-plugin==0.2.7",
     "asyncpg>=0.30.0",
     "line-bot-sdk>=3.19.0",
     "tboxsdk>=0.0.10",