Enable native tabbed window merging (macOS) (#55396)

Summary:
Pull Request resolved: #55396

Changelog:
[General][Changed] - **React Native DevTools**: Enable native macOS window merging

Reviewed By: motiz88

Differential Revision: D92154327

fbshipit-source-id: 1592f459584afc511167c1e7bc91be59a3b5c249

Author: huntie

packages/debugger-shell/src/electron/MainInstanceEntryPoint.js

@@ -68,6 +68,8 @@ function handleLaunchArgs(argv: string[]) {
       },
       // Icon for Linux
       icon: path.join(__dirname, 'resources', 'icon.png'),
+      // Enable tabs for this window (macOS 10.12+)
+      tabbingIdentifier: 'main',
     });
     // Auto-hide the Windows/Linux menu bar
     frontendWindow.setMenuBarVisibility(false);

packages/debugger-shell/src/electron/index.flow.js

@@ -20,6 +20,9 @@ const {app} = require('electron') as any;
 app.setName(pkg.productName ?? pkg.name);
 app.setVersion(pkg.version + '-' + buildInfo.revision);
 
+// Enable automatic tab support (macOS 10.12+)
+app.commandLine.appendSwitch('enable-features', 'TabStrip');
+
 // Handle global command line arguments which don't require a window
 // or the single instance lock to be held.
 const {