feat: add automatic charging protocol selection and event-driven monitoring

[HankAviator]

Changes on top of upstream

• Add Xiaomi-first automatic protocol detection with a single public-PPS fallback reconnect.
• Add detach debouncing so the software reconnect does not trigger another fallback.
• Replace the remaining 100 ms broadcast-worker polling with event-driven notifications.
• Add event-driven worker shutdown and clean thread joining.
• Fix the installer prompt timeout.
• Update the documentation and bump the version to 1.7.0.

Validation

Validated on a Xiaomi 14 with Xiaomi-only, public-PPS-only, and Xiaomi-plus-PPS chargers. Protocol priority, automatic fallback, idle efficiency, and clean shutdown all worked as expected.

[Seyud]

It is expected to be merged after the next release.