Show a notification warning the user to enable Shizuku after restarting the phone

[jojuniori]

Developer TODO (don't remove)

• write tests. put issue number in comment
• update documentation

Discord message link/email recipient

Describe the bug
Volume control is not working properly.
When I set the trigger of "double tap" and "long press" for the volume button respectively, the set event can be triggered normally, but the "short press" provided by the system cannot be triggered normally with the volume control.
At the same time, if I also set the "short press" mapping as volume control in the software, it will not trigger.
And at the moment if I pause the mapping using [TAP TO PAUSE] in the software, the system volume control goes back to normal.
But this wasn't a problem from the beginning, it didn't happen on the first day I used the software, it happened after I restarted the phone just now.

After this, I tried uninstalling the software and reinstalling and resetting it.
I found out the reason for this problem is that “Shizuku”, which the software relies on, doesn't start automatically when the phone is turned on after restarting the phone, so the user needs to turn on the service manually.
But “KeyMapper” can start automatically without checking whether the service of “Shizuku” is working properly, so it can't trigger the volume control without any error message at the same time.

To Reproduce
Steps to reproduce the behavior:
Reboot after setting up on an unrooted phone
key_mapper_report_20250115-041053.zip

Expected behavior
If the “Shizuku” service is detected to be incorrect, remind the user to turn it on manually.

Screenshots
Not have it because it just doesn't trigger any prompts.

Smartphone (please complete the following information):

• Device: [e.g. iQOO Neo 10]
• Android version: [e.g. Android 15]

Additional context
Add any other context about the problem here.
key_mapper_report_20250115-041053.zip

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