Preset renewal stored its target date as the old expiry plus the entered
days, while the authorization actually issued to the client is always
today plus a day count. For a license that had already expired, the
preset date was therefore in the past: SendPendingRenewal clamped the
day count to one, the client received a one-day license starting today,
but the renewal tip and the logs still printed the stale preset date.
The result was a message such as "renewed until 2026-05-30" while the
license really ran until tomorrow.
Presetting a renewal now bases the new date on today when the license
has already expired, and on the original expiry date otherwise, which
matches the one-day-per-day extension admins expect for live licenses.
The renewal dialog and the success prompt state which base was used, so
the computed date is never ambiguous. Renewal tips and both logging
paths (heartbeat-driven SendPendingRenewal and client-requested
GenerateRenewalInfo) now print the date that was actually issued, which
also corrects legacy preset records whose stored date has already
passed.
Co-Authored-By: deepseek-flash
