fix(adb): report failed app launches

[Xalzeroph]

What

launch_app() treated every app name present in APP_PACKAGES as a successful launch, even when adb shell monkey failed.

Why

That makes a failed Launch action look successful to the agent. A disconnected device returns a non-zero ADB status, and Monkey can also report monkey aborted when no launchable activity is found, but the previous code returned True in both cases.

Change

• return False when ADB exits non-zero
• treat an explicit monkey aborted result as a failed launch
• only apply the post-launch delay after a successful command
• add offline regression tests for ADB failure, Monkey abort, and success

Validation

• pytest -q tests/test_adb_device.py — 3 passed
• ruff 0.11.7 import sorting — passed
• ruff 0.11.7 format check — passed
• the new tests fail 2/3 on current main and pass 3/3 with this change

Fixes #424