Package returnmatch holds only DB-free, unit-tested logic so the
matching rules can be verified directly:
- Normalize() strips 【】（）()[] brackets and their content, strips
whitespace, converts fullwidth ASCII/space to halfwidth and
lowercases (issue #338 normalization rule), backtested against the
local real-pair samples quoted in the issue.
- SelectMatches() implements rules 2-6: caller-ordered (SYB created_at
DESC) processing, deadline-must-be-after-now filtering, earliest-
deadline-first selection among same-key candidates, and same-run
occupied-return exclusion; quantity never participates.
Covers the same-order multi-colour cross-pairing case explicitly
(TestSelectMatches_MultiColourSameOrderCrossPairing /
TestSYBSpecText) plus expired-deadline, earliest-first, occupied,
quantity-ignored and different-item-id cases.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NTDbDcwbDw1TSAcE6wfh2F
