Mount the DMG: Double-click your locally compiled .dmg file to mount it.
Install the App: Drag your Flutter .app bundle from the DMG window into your Applications folder.
Eject the DMG: Eject the disk image.
Trigger the Bypass: Go to your /Applications folder, Right-Click (or Control-Click) the app icon, and select Open.
Confirm: Instead of a hard block with no choice, a dialog box will appear saying "macOS cannot verify the developer..." but it will feature an explicit Open button. Click Open.
Note: Once you do this the first time, macOS remembers your choice, and the app will open normally with a standard double-click moving forward.
