* fix(time): prefer IANA timezone name over offset
When both headers are present, resolve x-tz-name with ZoneInfo and ignore
a conflicting numeric offset. The prompt label uses the resolved zone so
name and UTC offset cannot disagree.
Related: #6111
* test(calendar): cover IANA timezone precedence
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Co-authored-by: RaresKeY <158580472+RaresKeY@users.noreply.github.com>
