[HarshaMatta]

Ticket

Closes #5

What changed

I added two functions:

• didAttend checks if someone checked in after a meeting started and before midnight Eastern time.
• mergeCheckIns combines two check-ins, keeping the latest information without losing previous attendance.

I also added 25 tests covering normal check-ins, midnight, daylight saving time, invalid dates, and repeat check-ins.

How to verify

All tests and checks passed locally:

• 26 API tests passed
• 28 total tests passed
• TypeScript, lint, formatting, and build checks passed

Checklist

• Tests and checks passed
• TDD updated
• No private information included

[VidurShah]

Nice work Harsha. The rule is correct: at or after the start, on the same Eastern calendar day, using Intl with America/New_York and no hard-coded offset. The tests cover every case in the ticket, and then some, including the repeated 1 AM hour on Nov 1.

One small note: mergeCheckIns trusts the caller to pass the newer submission as incoming and doesn't compare timestamps. That's fine for the write path, so I pushed a doc comment saying so (65aa9ae) instead of changing behavior.

Good to merge.