- Introduced LoadedCapability class to manage plugin capabilities.
- Updated load_plugin function to discover and load capabilities alongside handlers.
- Enhanced Peer class to handle remote provided capabilities during initialization.
- Added tests for capability registration and invocation in legacy plugins.
- Improved MessageChain and message component handling in legacy plugins.
- Added comprehensive tests for legacy plugin integration and compatibility.
- Updated protocol messages to include provided capabilities in initialization.
- Enhanced top-level module imports to include capability-related functions.
- Updated `LegacyContext.send_message` to handle rich message chains using `send_chain`.
- Introduced `LegacyStar` class for backward compatibility with legacy plugins.
- Added `register` decorator for legacy plugin metadata.
- Enhanced `MessageChain` class with `to_payload` and `is_plain_text_only` methods.
- Updated `AstrMessageEvent.send` method to utilize `send_chain` for rich messages.
- Implemented `send_chain` method in `PlatformClient` for sending complex message structures.
- Added capability routing for `platform.send_chain`.
- Introduced tests for new functionality, ensuring compatibility with legacy plugins and message handling.
