Wi-Fi takeover on Android USB unplug

[Antoinegtir]

Why

We pre-pair Wi-Fi for Android USB devices, but unplugging mid-session still drops the flutter run. We want a true takeover: the adb tcpip endpoint should keep the session alive when USB goes away.

What

• On session start, if adb tcpip 5555 succeeds, remember the wireless host:port for the serial.
• On USB disconnect, transparently adb connect :5555 and re-attach the VM service.
• Snackbar: "Pixel 7 → Wi-Fi".

Constraints

• Skip for emulators (already excluded by emulator- prefix).
• Do not run adb tcpip on devices we did not initiate (no global side effects).

Acceptance

• Unplug USB during a run — session survives, hot reload works.
• Re-plug — transport migrates back to USB.
• No adb side effects on devices we did not touch.