MAX31855K: A Plausible Temperature Frame Can Still Have the Wrong Cold Junction

Unbuilt article/module design. No fabricated board, target execution or physical result.

Computer: run python3 test_actual_program.py from this folder. The tests import
the actual supplied program and exercise its pure logic/error paths.

Pico: review exact article wiring and current circuit-contract.json first.
Use original RP2040 Pico with MicroPython; copy max31855_lab.py to the board and
run it only with the specified low-voltage fixture. CPython host tests do not
build firmware or exercise the target peripherals.

All SVG/PNG diagrams are authored originals. Editable native EasyEDA source,
cloud identity/save/reopen, routed PCB and native rule checks are separate
root-operated artifacts and must be bound after actual native readback.
No fabrication order/purchase is included. Observations CSV is intentionally
blank. Never substitute a constructed test vector for a physical reading.
