feat(macos): add main window menu action

macos/Runner/AppDelegate.swift

@@ -138,9 +138,12 @@ class AppDelegate: FlutterAppDelegate, NSWindowDelegate {
     NSApp.terminate(nil)
   }
 
+  @IBAction func showMainWindow(_ sender: Any?) {
+    showMainWindow()
+  }
+
   func windowShouldClose(_ sender: NSWindow) -> Bool {
     sender.orderOut(nil)
-    NSApp.hide(nil)
     return false
   }
 

macos/Runner/Base.lproj/MainMenu.xib

@@ -313,6 +313,11 @@
                                     <action selector="performZoom:" target="-1" id="DIl-cC-cCs"/>
                                 </connections>
                             </menuItem>
+                            <menuItem title="Main Window" id="A7D-3k-pQm">
+                                <connections>
+                                    <action selector="showMainWindow:" target="Voe-Tx-rLC" id="mJr-qX-bH8"/>
+                                </connections>
+                            </menuItem>
                             <menuItem isSeparatorItem="YES" id="eu3-7i-yIM"/>
                             <menuItem title="Bring All to Front" id="LE2-aR-0XJ">
                                 <modifierMask key="keyEquivalentModifierMask"/>