feat: migrate to ZMK main (Zephyr 4.1 + LVGL 9)

[tokyo2006]

Summary

Migrate the nice_oled / nice_epaper / nice_custom shields from ZMK v0.3.0 (Zephyr 3.5 + LVGL 8.2) to ZMK main (Zephyr 4.1 + LVGL 9).

Changes

LVGL 8 → 9 migration

• lv_canvas_transform() (removed in LVGL 9) → lv_draw_sw_rotate() with LV_DISPLAY_ROTATION_270
• Canvas color format switched from true-color to LV_COLOR_FORMAT_L8 (the smallest format supported by lv_draw_sw_rotate), mirroring ZMK's own nice_view implementation
• lv_canvas_draw_* (removed) → layer-based canvas_draw_* wrappers (lv_canvas_init_layer → lv_draw_* → lv_canvas_finish_layer)
• Image assets: LV_IMG_CF_INDEXED_1BIT → LV_COLOR_FORMAT_I1; dropped the removed .header.always_zero / .header.reserved fields
• lv_draw_img_dsc_t/_init → lv_draw_image_dsc_t/_init, lv_anim_set_time → lv_anim_set_duration, LV_LABEL_LONG_SCROLL_CIRCULAR → LV_LABEL_LONG_MODE_SCROLL_CIRCULAR

ZMK API changes

• zmk_endpoints_selected() → zmk_endpoint_get_selected()

Fixes

• Bump ZMK_DISPLAY_DEDICATED_THREAD_STACK_SIZE from 2560 to 4096 — LVGL 9 rendering needs more stack; the old 2560 caused a hard fault on the split peripheral (broken display and unresponsive keyboard)
• Drop the unused lv_color_t cbuf[] parameter from draw_canvas (type mismatch after the buffer became uint8_t[])

Cleanup

• Removed redundant legacy widgets weather.c / media_player.c — they referenced the removed zmk/events/raw_hid.h API; weather and Spotify are already implemented via src/raw_hid + screen.c
• Wired up the sleep_status_bootloader.c variant behind a new CONFIG_NICE_OLED_SLEEP_STATUS_BOOTLOADER flag, and fixed its periodic-timer leak (now one-shot)
• Fixed a pre-existing Kconfig/CMake bug: SHOW_SLEEP_ART_ON_IDLE OR SHOW_SLEEP_ART_ON_IDLE → ..._ON_SLEEP (the _ON_SLEEP option never took effect)
• Removed stale Zephyr 3.x in-tree LVGL include paths from CMakeLists.txt

Notes

• ZMK main has no native Raw HID support; this module carries its own implementation, which is unchanged (the Zephyr 4.1 USB HID API is source-compatible with 3.5)
• lv_img_dsc_t, LV_IMG_DECLARE, lv_img_set_src, lv_obj_del, lv_obj_clear_flag, lv_txt_get_size etc. are intentionally kept as-is — they are auto-mapped by LVGL 9's src/lv_api_map_v8.h (the same mechanism ZMK's own nice_view relies on)
• Custom fonts are already LVGL 9-compatible (generated with version conditionals)

Testing

• Migration verified against ZMK main nice_view (authoritative reference for the same 68×160 → 160×68 rotation)
• Build + runtime verified on hardware (central + split peripheral)
• Reviewer: confirm OLED (nice_oled) and nice!view (nice_epaper) both render correctly

[tokyo2006]

I only test my nice_oled and passed

[ramb0t]

Tested this branch on a Sofle Choc RGB wireless (nice!nano v2, both halves nice!view,
sofle_left/right nice_view_adapter nice_epaper) against ZMK main
641514a9 / zephyr fork 10ba6d0c. It builds and renders correctly —
thanks for doing the LVGL 9 work.

It did not run, though, until I overrode two Kconfig values. Both halves
drew one correct frame and then froze about a second later, every boot.

The resolved .config from CI shows:

CONFIG_NICE_EPAPER_ON=y
CONFIG_LV_Z_VDB_SIZE=64
CONFIG_ZMK_DISPLAY_DEDICATED_THREAD_STACK_SIZE=3072

NICE_OLED_ON is unset in that same .config, so Kconfig.defconfig:23-26
should have selected default 100 if NICE_EPAPER_ON and :59-61 / :257-258
should have given 4096. Neither default took effect. LV_Z_MEM_POOL_SIZE is
unaffected and keeps the intended 8192 central / 4096 peripheral split.

Adding these two to my own .conf fixes it completely — no freezes since:

CONFIG_LV_Z_VDB_SIZE=100
CONFIG_ZMK_DISPLAY_DEDICATED_THREAD_STACK_SIZE=4096

4096 exactly, so this is the number the module already asks for rather than
me padding it.

Two things that may point at the cause:

nice_epaper.conf already carries both lines under the "modo dongle" TODO
block, but commented out:

# CONFIG_LV_Z_MEM_POOL_SIZE=8192
# CONFIG_ZMK_DISPLAY_DEDICATED_THREAD_STACK_SIZE=4096

And ZMK's own boards/shields/nice_view/nice_view.conf sets
CONFIG_ZMK_DISPLAY_DEDICATED_THREAD_STACK_SIZE=4096 as a .conf
assignment. Swapping nice_view for nice_epaper drops that, and the
Kconfig.defconfig default does not appear to replace it — ZMK declares an
unconditional default 3072 in app/src/display/Kconfig.

So the fix may be as simple as uncommenting those two lines in
nice_epaper.conf and adding CONFIG_LV_Z_VDB_SIZE=100 alongside them,
since a .conf assignment wins where the default did not.