添加模型分割

client/gui/widgets/LongPressSwitchToolButton.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <QToolButton>
+
+class QMouseEvent;
+class QTimer;
+
+/**
+ * 可复用的工具栏按钮：短按行为与普通 QToolButton 一致；
+ * 左键按住超过设定时间（默认 450ms）且仍未松开时发出 longPressTriggered()，
+ * 用于在「同一工具钮」上切换子模式（类似 Photoshop 长按切换同类工具）。
+ */
+class LongPressSwitchToolButton final : public QToolButton {
+    Q_OBJECT
+public:
+    explicit LongPressSwitchToolButton(QWidget* parent = nullptr);
+
+    void setLongPressInterval(int ms);
+    int longPressInterval() const { return m_intervalMs; }
+
+signals:
+    void longPressTriggered();
+
+protected:
+    void mousePressEvent(QMouseEvent* event) override;
+    void mouseReleaseEvent(QMouseEvent* event) override;
+
+private:
+    QTimer* m_timer = nullptr;
+    int m_intervalMs = 450;
+    bool m_longPressEmittedForThisPress = false;
+};