Add a fuel command to estimate how much fuel a cook will burn

[jongio]

Adds an offline fuel command that estimates how much fuel a cook will burn, so you can pack enough pellets, charcoal, or wood before you light the pit.

What it does

• New pure SDK helper estimateFuel(pitTempF, hours, { fuelType, hopperLb }) picks a burn rate from temperature bands per fuel type, multiplies by the cook length, and adds a buffer for the amount to pack.
• With a --hopper size it also reports how long one load lasts and how many refills to plan.
• CLI: thermoworks fuel --temp 225 --hours 12 [--fuel pellet|charcoal|wood] [--hopper 20] [--list] [--json].

Notes

• No login or network. Deterministic math with RangeError on bad input.
• Burn rates are working approximations for common pits, not a meter.

Tests

• SDK: tier selection, boundary inclusivity, totals, buffer rounding, hopper runtime and refills, validation.
• CLI: arg parsing, format output, JSON, list, and required-flag errors. Registry coverage updated.

Closes #294

[jongio]

Closing. Keeping the thermoworks CLI focused on device and temperature features: probes, alarms, device health, and live and archived readings. A fuel estimator doesn't read device data, so it's out of scope for this repo.