优化: aichat 打磨收尾(切换信任保留 + save并发串行 + 后台授权守卫 + 分离窗口失效 + 气泡截图复制)

src-tauri/src/commands/ai/conversation.rs

@@ -196,7 +196,7 @@ pub(crate) async fn save_conversation(
     // 超时即放弃本次 save,下次 loop 轮次会重新落库,幂等覆盖无副作用)。
     if let Err(_elapsed) = tokio::time::timeout(
         Duration::from_secs(SAVE_CONVERSATION_TIMEOUT_SECS),
-        save_conversation_inner(session_arc, db, conv_id, usage, model, touch_updated_at),
+        save_conversation_serialized(session_arc, db, conv_id, usage, model, touch_updated_at),
     )
     .await
     {
@@ -208,6 +208,23 @@ pub(crate) async fn save_conversation(
     }
 }
 
+/// 按 conv 串行化 save(取 per-conv 锁后执行 inner;tokio Mutex lock 可取消,超时放弃不持锁)。
+async fn save_conversation_serialized(
+    session_arc: &Arc<Mutex<AiSession>>,
+    db: &Arc<Database>,
+    conv_id: &str,
+    usage: Option<&df_ai::provider::TokenUsage>,
+    model: Option<&str>,
+    touch_updated_at: bool,
+) {
+    let save_lock = {
+        let mut session = session_arc.lock().await;
+        session.save_lock(conv_id)
+    };
+    let _save_guard = save_lock.lock().await;
+    save_conversation_inner(session_arc, db, conv_id, usage, model, touch_updated_at).await;
+}
+
 /// save_conversation 内部实现(无超时,由外层 save_conversation 包 timeout 调用)。
 async fn save_conversation_inner(
     session_arc: &Arc<Mutex<AiSession>>,