新增: AI Chat多项增强(审批去重/编辑重发/导出/实体引用/会话置顶搜索)+任务推进链df-nodes落地

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

@@ -138,6 +138,7 @@ pub(crate) async fn save_conversation(
                 model: model.map(|m| m.to_string()),
                 models: model.map(|m| serde_json::to_string(&[m]).unwrap_or_else(|_| "[]".to_string())),
                 archived: false,
+                pinned: false,
                 prompt_tokens: usage.map(|u| u.prompt_tokens as i64),
                 completion_tokens: usage.map(|u| u.completion_tokens as i64),
                 created_at: created_at.unwrap_or_else(|| now.clone()),