[gcormier]

Adds a toolbox display preset for the GDEY042Z98 / DEPG0420 4.2" B/W/R panel (SSD1683), as fitted to some RockBase IoT NM-EPD-420 boards.

Requires firmware that maps panel IC 0x004D to bb_epaper's EP42R3_400x300: OpenDisplay/Firmware#173.

Changes

• config.yaml: add panel_ic_type 77, ep42r3_400x300.
• simple-config-presets.json: add the ep42r-400x300 preset, "4.2" BWR GDEY042Z98 (400×300)": 84×63 mm active area, color_scheme 1 (bwr), full updates only.
• simple-config-id-registry.json: register ep42r-400x300 as index 47.

Testing

On an NM-EPD-420 with a GDEY042Z98 panel, running the firmware from OpenDisplay/Firmware#173:

• Served the toolbox locally from this branch and confirmed the preset is listed and loads.
• Encoded a config from the NM-EPD-420 driver preset (32), this display preset (47) and USB power (1) with the firmware repo's tools/od-device-cli.py encode-config, then flashed it as a factory embed. BLE scanning wasn't available on the test machine, so it wasn't written through the toolbox's Bluetooth path.
• The panel boots and renders correctly: black/white/red test boxes in the right colours, text not mirrored, full frame.

Unrelated note

config.yaml documents system_config.device_flags bit 5 (0x20) as channel_sounding, but the NM-EPD-420 driver preset sets device_flags: 0x20 and the firmware reads that bit as DEVICE_FLAG_NM420_INIT (the boot log prints Device flag DEVICE_FLAG_NM420_INIT is set, calling nm420_init()). One of the two is out of date. I haven't changed it here.