Description

Fixes #310

The get() method in RateLimiterDynamo was returning expired items instead of null. DynamoDB's TTL cleanup can take up to 48 hours, so the library must validate expiration timestamps client-side.

Problem

The _get() method checked if an item exists but never validated the expire timestamp, causing:

• Rate limits to persist beyond their intended duration

Solution

Added expiration validation in _get():

• Return null if item.expire <= currentTime
• Treat -1 as never-expiring (unchanged)