Send Sina Message
Sends a user message to Sina AI and retrieves the response.
Request
final response = await apiService.sendSinaMessage(
sessionId: \"session-123\",
message: \"I have a headache, what should I do?\"
);
Response Structure
Returns a SinaMessage object containing:
- id: (int) Message ID.
- text: (String) The response text from Sina.
- sender: (String) "sina".
- chatId: (String) Session ID.
- createdAt: (String) ISO timestamp.
Error Handling
Throws a HttpResponseException if the request fails or if the session is invalid.