Add 'Beep on arrival' toggle for ratgdo32-disco boards

[mav2287]

Summary

• The ratgdo32-disco buzzer beeps on every vehicle arrival with no way to disable it independently of the closing delay safety beep. This adds a new "Beep on arrival" switch that controls whether the arrival beep plays, while leaving the closing delay beep unaffected.
• Defaults to ON for backwards compatibility — existing users see no behavior change unless they explicitly toggle it off.
• Setting persists across reboots via ESPHome preferences.
• Shows in ESPHome web UI and Home Assistant as a config switch (alongside LED, LASER, etc.).

Changes

• ratgdo.h / ratgdo.cpp — Add beep_on_arrival observable, getter/setter, and subscribe method (inside RATGDO_USE_VEHICLE_SENSORS guard)
• switch/ratgdo_switch.h / ratgdo_switch.cpp / __init__.py — Add RATGDO_BEEP_ON_ARRIVAL switch type with preference persistence
• output/ratgdo_output.cpp — Gate the vehicle arrival beep on get_beep_on_arrival()
• All 6 v32disco YAML files (root + static/) — Add the new switch entry

Test plan

• Beep on arrival defaults to ON (backwards compatible)
• Toggling OFF prevents beep when vehicle arrives
• Closing delay beep still works regardless of this setting
• Setting persists across reboots
• Shows in ESPHome web UI and Home Assistant as a config switch

🤖 Generated with Claude Code

[PaulWieland]

Build failure has to be fixed before this can be merged.

[mav2287]

@PaulWieland should be good now, take a look and let me know.