Add Jest testing framework with comprehensive regex-focused unit tests for callsign.js#15

phieri merged 3 commits intomainphieri/callsign.js:mainfrom

copilot/fix-bd38b13f-70ca-49a4-87df-d6d4f07d4ad2phieri/callsign.js:copilot/fix-bd38b13f-70ca-49a4-87df-d6d4f07d4ad2Copy head branch name to clipboard