* refactor: restructure chat components for improved modularity

- Replaced existing chat message components with new modular components: `MessageAssistant`, `MessageList`, `MessageUser`, and `MessageFooter`.
- Introduced new parts for handling message content: `MessageTextPart`, `MessageReasoningPart`, and `ToolCallPart`.
- Enhanced the `DecoChatPanel` to utilize the new components, improving readability and maintainability of the chat interface.
- Added a `ConnectionCard` and `ToolOutputRenderer` for better handling of tool outputs and connections in chat messages.

These changes enhance the overall structure and functionality of the chat system.

* ai

* fix: improve error handling and clipboard copy functionality

- Updated error message handling in ToolCallPart to simplify type checking for errorText.
- Refactored CopyButton in ToolOutputRenderer to implement a robust clipboard copy mechanism with fallback support, enhancing user experience when copying text.

* refactor: simplify error message handling in ToolCallPart

- Updated type checking for errorText in ToolCallPart to enhance code clarity and maintainability.