refactor: expand market-api-routes tests with state injection

Expand from 36 to 52 test steps using MarketState injection pattern.
New coverage: matching (partial, FIFO, multi-match), FROST mock resolution,
user pairs in detail, full lifecycle (YES/NO resolution + redeem).

247 CI tests / 847 steps passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: motxx