Warn when an order is below the program's minContracts

[piekstra]

The gap

An order smaller than the program's minContracts rests happily, qualifies its
side, and scores nothing. Nothing in the output said so.

It's near-invisible after the fact: the reward share simply fails to move. Worse,
because the order book aggregates same-price levels, the sub-minimum tokens end up
counted toward the competing score instead — so the mistake both earns nothing
and dilutes the orders that do earn.

Why an advisory and not a rail

A sub-minimum order is frequently correct. A 1-token ask is the cheapest possible
way to hold a side open for two-sided eligibility — the standard shape for parked
recovery inventory. Refusing it would break a pattern that is deliberately used.

Intent can't be inferred here, so this states the consequence and lets the operator
judge, rather than demanding an override flag for something that is often right.

Behaviour

• prints before the confirmation prompt, so --force runs see it too
• folded into the prompt text for interactive runs
• silent for properties running no reward program
• never blocks an order if the program lookup fails

⚠ 3 token(s) is below this property's minContracts (4). The order will QUALIFY
  its side for two-sided eligibility but score NOTHING toward LP rewards.
  Use at least 4 to earn on it.

Tests

Pure rule split into min_contracts_note_from so it's testable without a client:

• sub-minimum order is flagged (qualifies / scores nothing)
• at or above the bar is silent, and thresholds are per-property
• unknown property, empty payload, and malformed payload all stay silent

Follows the same shape as the market-price and slippage rails: check before the
mutation, say plainly what the consequence is.