Receive diagonal right swipe fails the documented wraparound step #1667

Observed behavior

The documented Savings → USDT right diagonal swipe does not select USDT. Savings remains selected and Receive stays open. Horizontal wraparound, the opposite USDT → Savings diagonal and QR tap-to-copy work.

Reported by the exact-head device review of #1564 at c1f1c0a784a04107617eccef5fdc698b9dc08789 on Android 16, both default and compact displays. Recording with failing diagonal and successful controls.

Reproduction

Follow journeys/receive/receive-tabs-wraparound.xml with USDT enabled, no open Spending channel/CJIT invoice and no hardware wallet paired (Savings, Spending, USDT tabs):

1. Open Receive on Savings on a 1080 × 2400 display.
2. Start inside the top-left QR area, away from the system back edge: adb shell input swipe 100 720 950 200 1200.
3. The journey expects USDT selected and Receive still open. The reported result is Savings still selected.
4. Compare a horizontal right swipe; it wraps correctly. The opposite diagonal from USDT also works.

Investigation and scope

ReceiveQrScreen.kt and SwipeToChangeTabModifier.kt are identical in the tested #1564 head, its base 22a5cb561 and current master d5526d409. The BTC pages use the snapping LazyRow; the USDT page uses a separate swipe callback. A gesture-selection/cancellation cause has not been established. Source equality was independently checked; the linked device report supplies the reproduction evidence.

Investigate against the documented journey before changing gesture thresholds or the shared sheet. Preserve horizontal paging, system-back behavior, tap-to-copy and sheet dismissal. Check the corresponding iOS journey; no iOS failure is claimed. This is not an introduced #1564 regression and is separate from #1535's bottom-control/label stability and #1588's receive edit transition.