Button Handling with CH32v003

## Summary
Rework hdw-btn and related hw API for the CH32 to do the button processing instead of the ESP32.

## Technical Spec
Currently the button info is a [bitmask](https://adam.feinste.in/Super-2024-Swadge-FW/hdw-btn_8h.html#a434eef640087504b945dd322ba6ce390) starting at PB_UP. The GPIO is defined in [initButtons](https://adam.feinste.in/Super-2024-Swadge-FW/hdw-btn_8h.html#a36495b0c8ced885ad04274d06929f588). I'm not sure we want to tear out the ESP32 GPIO support for the buttons, but perhaps we can add an option for the CH32? I dunno, you're the real programmer, I just work here.

## UI
NA

## How to Test

Start with `hdw-btn.h` and the `initButtons` declaration/usage, since the issue points to them directly. Then trace the button bitmask and GPIO flow in the ESP32 and CH32v003 hardware paths to identify where button processing is currently fixed to ESP32. No test is named in the issue, so the first check is the relevant hw-input startup/build flow for each target, and completion means CH32 handles button processing via the hw API (or with an explicit option) without breaking ESP32 behavior.

Scritto dal modello di indicizzazione a partire dal testo della issue.