调整公共模块结构，方便后续延伸

service/src/core/context.rs

@@ -2,7 +2,7 @@ use std::sync::OnceLock;
 
 use tokio::sync::Mutex;
 
-use common::ai::{ChatCompletionRequestMessage, ChatCompletionToolCall};
+use common::model::ai::{ChatCompletionRequestMessage, ChatCompletionToolCall};
 
 static CHAT_CONTEXT: OnceLock<Mutex<Vec<ChatCompletionRequestMessage>>> = OnceLock::new();
 
@@ -24,11 +24,8 @@ pub async fn add_assistant_message(
     content: String,
     tool_calls: Option<Vec<ChatCompletionToolCall>>,
 ) {
-    let message = ChatCompletionRequestMessage::assistant(
-        "assistant".to_string(),
-        content,
-        tool_calls,
-    );
+    let message =
+        ChatCompletionRequestMessage::assistant("assistant".to_string(), content, tool_calls);
     push_context_message(message).await;
 }