v0.7.1: fix noisy warning for index combinations not matching a specimen
Fix: deduplicate "No Specimens for combo" warning (Fixes #9) Replace per-sequence WARNING with single end-of-run summary. Add __repr__ to PrimerInfo for readable log output. Bump version to 0.7.1. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>