Rename CACHE_ONE_YEAR for clarity and fix usage (#89450)
This renames the variable for clarity as we've had issues with unit
mismatch with this constant specifically. Also fixes usage which was
working accidentally because we converted it to a negative unit which is
always in the past.
x-ref: [slack
thread](https://vercel.slack.com/archives/C02K2HCH5V4/p1770137071766599?thread_ts=1769515738.350369&cid=C02K2HCH5V4)
