The provider Cost history section shows the newest seven days and
highlights the highest of them, but its peak line searched the whole
range. With a 30-day range, an older expensive day became the named
peak while the rows showed and highlighted a different one.

Both now read the same span through CostPresentation.recentHistoryPoints.
The daily average still covers the whole range, as documented.

Documentation impact: CHANGELOG Unreleased Fixed entry; the cost-history
guide states the rows' span, the peak, and the average's range. TODO.md
is unaffected: no tracked entry covers this.

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>