fix(ios): report a scroll's clipped band in its response

Author: thymikee

apple/runner/AgentDeviceRunner/AgentDeviceRunnerUITests/RunnerScrollViewportPolicy.swift

@@ -59,6 +59,25 @@ enum ScrollGestureOutcome {
   case occluded(keyboardMinY: Double, visibleHeight: Double)
 }
 
+extension ScrollGestureDispatch {
+  /// Reports the gesture against the band its plan ran inside, beside the keyboard evidence. The
+  /// synthesis frame stays the full viewport so the coordinates rotate correctly, which leaves the
+  /// payload measured against an axis the caller never planned on: `pixels` are a fraction of the
+  /// band, so the band is what `referenceWidth` and `referenceHeight` have to name.
+  func attachingEvidence(to response: Response) -> Response {
+    guard response.ok else { return response }
+    var payload = response.data ?? DataPayload()
+    payload.referenceWidth = Double(planFrame.width)
+    payload.referenceHeight = Double(planFrame.height)
+    guard let keyboardMinY else {
+      return Response(ok: response.ok, data: payload, error: response.error)
+    }
+    payload.keyboardAvoided = true
+    payload.keyboardMinY = keyboardMinY
+    return Response(ok: response.ok, data: payload, error: response.error)
+  }
+}
+
 extension RunnerScrollViewport {
   /// Plans the swipe inside the band the keyboard left and keeps the viewport as the coordinate basis,
   /// so a clip shortens the travel without moving the gesture's lane.
@@ -338,6 +357,22 @@ extension RunnerTests {
       "a landscape swipe must stay clear of the keys"
     )
 
+    let reported = gesture.attachingEvidence(
+      to: Response(
+        ok: true,
+        data: DataPayload(referenceWidth: viewport.width, referenceHeight: viewport.height),
+        error: nil
+      )
+    )
+    XCTAssertEqual(
+      reported.data?.referenceHeight,
+      band.height,
+      "the payload names the band the plan ran inside, not the synthesis frame"
+    )
+    XCTAssertEqual(reported.data?.referenceWidth, viewport.width)
+    XCTAssertEqual(reported.data?.keyboardMinY, keyboardMinY)
+    XCTAssertEqual(reported.data?.keyboardAvoided, true)
+
     let orientedStartY = gesture.planFrame.minY + gesture.plan.y1
     let dispatched = nativeSynthesizedPoint(
       orientedX: gesture.planFrame.minX + gesture.plan.x1,

apple/runner/AgentDeviceRunner/AgentDeviceRunnerUITests/RunnerTests+CommandExecution.swift

@@ -1983,8 +1983,8 @@ extension RunnerTests {
         guard scrollDurationIsValid(command.durationMs) else {
           return invalidScrollDurationResponse(commandName: "scroll")
         }
-        return attachingScrollViewportEvidence(
-          executeScrollDragGesture(
+        return gesture.attachingEvidence(
+          to: executeScrollDragGesture(
             activeApp: activeApp,
             x: gesture.planFrame.minX + gesture.plan.x1,
             y: gesture.planFrame.minY + gesture.plan.y1,
@@ -1994,8 +1994,7 @@ extension RunnerTests {
             message: "scrolled",
             context: scrollContext.withReferenceFrame(gesture.coordinateFrame),
             releaseBehavior: command.scrollReleaseBehavior
-          ),
-          keyboardMinY: gesture.keyboardMinY
+          )
         )
       }
     case .desktopScroll:
@@ -2575,14 +2574,6 @@ extension RunnerTests {
   /// Adds the #2500 avoidance evidence to a scroll response. Only the frame resolver knows whether
   /// it trimmed the swipe for a keyboard, and only `scroll` has this evidence to carry, so it is
   /// attached where the frame was resolved rather than threaded through every gesture response.
-  private func attachingScrollViewportEvidence(_ response: Response, keyboardMinY: Double?) -> Response {
-    guard response.ok, let keyboardMinY else { return response }
-    var payload = response.data ?? DataPayload()
-    payload.keyboardAvoided = true
-    payload.keyboardMinY = keyboardMinY
-    return Response(ok: response.ok, data: payload, error: response.error)
-  }
-
   /// The refusal a keyboard forces. It performs no gesture: swiping into the keys would leave the
   /// surface where it was, which the daemon's no-progress fingerprint reads as a stuck container
   /// (#2499) and an agent reads as a broken scroll. The TS owner maps the code to the