feat: move odfu example from note-outboard-dfu and update readmes

[rdlauer]

Migrating ODFU example from note-outboard-dfu repo

[Bucknalla]

Let's use the Fluent API which covers all four requests used here (hub.set, card.dfu, card.aux, dfu.status), and it's the target pattern for note-python users (see examples/binary-mode/upload/binary_upload_example.py) instead of hand-building {"req": ...} dicts + card.Transaction().

Suggested rewrite of configure_outboard_dfu (and the related import/var changes) in circuit-python/code.py:

importtimeimportboardimportdigitalioimportnotecardfromnotecardimportcard, dfu, hub# The unique Product Identifier for your device. Claim one in a Notehub project.productUID="com.your-company.your-project"# The firmware version reported to Notehub via dfu.status. Bump this (and change# BLINK_DELAY) when you build a new image to update to.FIRMWARE_VERSION="1.0.0"# Seconds the LED stays on/off. Change this to make the update visually obvious.BLINK_DELAY=0.5defconfigure_outboard_dfu(nCard):
"""Put the Notecard online and enable Outboard Firmware Update for the host. Outboard Firmware Update requires the Notecard to be in "continuous" or "periodic" mode. On a Notecarrier F the DFU signals are routed over the Notecard's shared AUX pins, so card.dfu uses mode "aux" and card.aux is set to "off" to free those pins for DFU. """hub.set(nCard, product=productUID, mode="continuous", sn="circuitpython-notecard")
# Enable Outboard Firmware Update and tell the Notecard the host MCU type.card.dfu(nCard, name="stm32", on=True, mode="aux")
# Free the AUX pins so they can be used for Outboard Firmware Update.card.aux(nCard, mode="off")
# Enable host DFU and report the running firmware version to Notehub.dfu.status(nCard, on=True, version=FIRMWARE_VERSION)
defmain():
"""Enable Outboard DFU, then blink the built-in LED as the update payload."""i2c=board.I2C()
nCard=notecard.OpenI2C(i2c, 0, 0, debug=True)
configure_outboard_dfu(nCard)
led=digitalio.DigitalInOut(board.LED)
led.direction=digitalio.Direction.OUTPUTprint("Running firmware version {}. Hit CTRL-C to stop.".format(FIRMWARE_VERSION))
whileTrue:
led.value=Truetime.sleep(BLINK_DELAY)
led.value=Falsetime.sleep(BLINK_DELAY)
main()

Note the parameter/variable rename from card to nCard (matching the README's fluent API example) — it was renamed to avoid colliding with the notecard.card module import.

[Bucknalla]

See comment re-changing to Fluent API

[rdlauer]

@Bucknalla I missed your complete code sample but Claude added the fluent API usage for me. Also while in here I updated the github actions to the latest versions to avoid the Node 20 deprecation warnings. Ready for a review.