feat: support custom shortcut for existing actions

Resolve https://github.com/BLumia/pineapple-pictures/issues/128

Actually also https://github.com/BLumia/pineapple-pictures/issues/72
but not sure why that one is now a 404 page.

app/shortcutedit.h

@@ -0,0 +1,54 @@
+// SPDX-FileCopyrightText: 2024 Gary Wang <opensource@blumia.net>
+//
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <QWidget>
+#include <QList>
+#include <QKeySequence>
+
+class QLabel;
+class QFormLayout;
+class QToolButton;
+class QKeySequenceEdit;
+class ShortcutEdit;
+class ShortcutEditor : public QWidget
+{
+    Q_OBJECT
+public:
+    explicit ShortcutEditor(ShortcutEdit * shortcutEdit, QWidget * parent = nullptr);
+    ~ShortcutEditor();
+
+    void setDescription(const QString & desc);
+
+    void reloadShortcuts();
+    void applyShortcuts();
+
+private:
+    QLabel * m_descriptionLabel;
+    ShortcutEdit * m_shortcutEdit;
+    QFormLayout * m_shortcutLayout;
+    QList<QKeySequenceEdit *> m_keySequenceEdits;
+};
+
+class ShortcutEdit : public QWidget
+{
+    Q_OBJECT
+    Q_PROPERTY(QList<QKeySequence> shortcuts MEMBER m_shortcuts WRITE setShortcuts NOTIFY shortcutsChanged)
+public:
+    explicit ShortcutEdit(QWidget * parent = nullptr);
+    ~ShortcutEdit();
+
+    QList<QKeySequence> shortcuts() const;
+    void setShortcuts(const QList<QKeySequence> &shortcuts);
+
+signals:
+    void shortcutsChanged();
+    void editButtonClicked();
+
+private:
+    QList<QKeySequence> m_shortcuts;
+    QLabel * m_shortcutsLabel;
+    QToolButton * m_setShortcutButton;
+};