v1.26.0 -- POS Activity dashboard

"POS Activity dashboard" release. The POS Activity admin page becomes a full operations dashboard: today's KPI counters with an hourly revenue chart, a pace curve against the same hour yesterday, a weekly trend, channel and tender splits, and a date selector that anchors the whole view on a chosen day.

Mobile. Zero mobile/ diffs on this release. The current mobile build (version 1.19.0, versionCode 9) remains current; no new APK for v1.26.0.

Changed

• POS Activity dashboard revamp (#413): the POS Activity page is reworked from a flat list into an operations dashboard. The top bar carries today's KPI counters (sales count and revenue, average sale, refunds, active terminals) and an hourly revenue chart; below it sit a pace curve against the same hour yesterday, a weekly trend, and channel and tender splits. A date selector anchors the KPIs, the sales-order list, and the analytics on a chosen day. The /api/admin/pos/summary endpoint computes the new aggregates in one pass and /api/admin/pos/sales-orders gains the matching date and channel filters; both keep the pos-activity page-permission gating.