fix(udev): restrict mode switching to intended devices and events

Take the aic.rules portion of #129: restrict 1111:1111 switching to
88M80 USB devices, target the event's bus/device address, and eject only
whole disks on add. Add selection fixtures and document the product
restriction. Keep installer paths and existing firmware handling unchanged.

Co-authored-by: rtk94 <richardtknepp@gmail.com>
(cherry picked from commit e2c5835767)

README.md

@@ -85,6 +85,11 @@ commands. Existing users must rerun `sudo ./install.sh` to replace the installed
 usb_modeswitch configuration, then unplug the adapter completely and plug it
 back in.
 
+Automatic switching requires the USB product string to start with `88M80`.
+Unrelated flash disks also use `1111:1111`, so that USB ID alone is not enough.
+If your adapter reports a different product string, verify its identity before
+trying the manual command below.
+
 If automatic switching does not occur, try the same sequence manually:
 
 ```bash