Completes the internal-pull emulation for the common case (a button on an
RTC-capable GPIO like 4/15/25/... with INPUT_PULLUP):
- Backend reads the RTC_IO pad RUE/RDE bits via the new
get_internals(QEMU_INTERNAL_RTCIO) and emits gpio_pull for RTC pins, so
pull-up/down on those pads is finally visible (it lives in RTC_IO, not
IO_MUX). IO_MUX path still covers non-RTC pins.
- The digitalRead path is driven by seeding the GPIO input level, not by
SPICE. The part-level INPUT_PULLUP seed (BasicParts) is sent at attach,
before the multi-second QEMU boot finishes, so it is lost and the pin
reads LOW. makePinPullHandler now drives the pin to the pull's idle level
via sendPinEvent when the guest programs the pull (post-boot), so it
sticks. A real button press/release still overrides it.