Enable jpegio in zephyr port

[FoamyGuy]

Added a native_sim test to validate the decoding.

Also updated the jpegio docstrings example to contain the remaining steps to show the jpeg on a display.

[tannewt]

Thank you!

[FoamyGuy]

Not sure why the nordic_nrf54h20dk build shows failing now. The tail end of the log (https://github.com/adafruit/circuitpython/actions/runs/24542014373/job/71836502949?pr=10952#step:10:22451) looks like a pretty normal successful build to my eye but shows Error: Process completed with exit code 2. with no other error info that I could find.

I am able to successfully build the nordic_nrf54h20dk locally. Though I do notice the end of the output has a bit different numbers inside the square brackets for some steps as compared to the actions run, not sure if it means anything.

[344/344] Linking C executable zephyr/zephyr.elf
Memory region         Used Size  Region Size  %age Used
           FLASH:      401044 B       392 KB     99.91%
             RAM:       60536 B       760 KB      7.78%
     DEVNULL_ROM:         816 B       256 KB      0.31%
   DMA_RAM3x_APP:         296 B         4 KB      7.23%
        APP_RAM0:          0 GB      32512 B      0.00%
  PMLocalRamfunc:          0 GB        192 B      0.00%
pm_s2ram_context:          0 GB         32 B      0.00%
        IDT_LIST:          0 GB        32 KB      0.00%
Generating files from /home/timc/repos/circuitpython/circuitpython_again/circuitpython9/ports/zephyr-cp/build-nordic_nrf54h20dk/zephyr-cp/zephyr/zephyr.elf for board: nrf54h20dk/nrf54h20/cpuapp
[13/16] Performing build step for 'uicr'
[1/1] Using gen_uicr.py to generate /home/timc/repos/circuitpython/circuitpython_again/c...again/circuitpython9/ports/zephyr-cp/build-nordic_nrf54h20dk/zephyr-cp/zephyr/zephyr.elf
[16/16] Completed 'uicr'

[dhalbert]

@FoamyGuy The raw logs show a flash overflow, but the regular log does not, which is weird.
Raw logs:
https://productionresultssa15.blob.core.windows.net/actions-results/86f7c0d3-3cc5-4099-b92d-588dee8c10d5/workflow-job-run-3fd48b21-331f-5635-9318-2e85f1a54eaf/logs/job/job-logs.txt?rsct=text%2Fplain&se=2026-04-17T15%3A04%3A47Z&sig=%2BFoRUWattfgSeOQokQlhh20MKWwnNM2aDI8QmgOq2%2Fs%3D&ske=2026-04-17T16%3A49%3A12Z&skoid=ca7593d4-ee42-46cd-af88-8b886a2f84eb&sks=b&skt=2026-04-17T12%3A49%3A12Z&sktid=398a6654-997b-47e9-b12b-9515b896b4de&skv=2025-11-05&sp=r&spr=https&sr=b&st=2026-04-17T14%3A54%3A42Z&sv=2025-11-05
The "Explain error" Copilot button found this.

[FoamyGuy]

Ahh, thank you, I disabled jpegio for nordic_nrf54h20dk in latest commits.