fix: keep in-page swipes on visible content

Author: thymikee

src/__tests__/runtime-interactions.test.ts

@@ -609,12 +609,12 @@ test('runtime gesture swipe presets use stable viewport lanes', async () => {
     session: 'default',
   });
 
-  assert.deepEqual(pageSwipe.from, { x: 85, y: 65 });
-  assert.deepEqual(pageSwipe.to, { x: 15, y: 65 });
+  assert.deepEqual(pageSwipe.from, { x: 85, y: 50 });
+  assert.deepEqual(pageSwipe.to, { x: 15, y: 50 });
   assert.deepEqual(edgeSwipe.from, { x: 8, y: 50 });
   assert.deepEqual(edgeSwipe.to, { x: 85, y: 50 });
   assert.deepEqual(calls, [
-    { from: { x: 85, y: 65 }, to: { x: 15, y: 65 }, durationMs: 300 },
+    { from: { x: 85, y: 50 }, to: { x: 15, y: 50 }, durationMs: 300 },
     { from: { x: 8, y: 50 }, to: { x: 85, y: 50 }, durationMs: 350 },
   ]);
 });
@@ -634,9 +634,9 @@ test('runtime iOS in-page swipe presets avoid edge-navigation lanes', async () =
     session: 'default',
   });
 
-  assert.deepEqual(pageSwipe.from, { x: 15, y: 65 });
-  assert.deepEqual(pageSwipe.to, { x: 85, y: 65 });
-  assert.deepEqual(calls, [{ from: { x: 15, y: 65 }, to: { x: 85, y: 65 }, durationMs: 300 }]);
+  assert.deepEqual(pageSwipe.from, { x: 15, y: 50 });
+  assert.deepEqual(pageSwipe.to, { x: 85, y: 50 });
+  assert.deepEqual(calls, [{ from: { x: 15, y: 50 }, to: { x: 85, y: 50 }, durationMs: 300 }]);
 });
 
 test('runtime viewport gestures reject inspect-only macOS surfaces', async () => {

src/core/__tests__/dispatch-interactions.test.ts

@@ -116,12 +116,12 @@ test('handleSwipePresetCommand resolves Android in-page swipe to content lane',
     undefined,
   );
 
-  assert.deepEqual(calls, [[340, 520, 60, 520, 300]]);
+  assert.deepEqual(calls, [[340, 400, 60, 400, 300]]);
   assert.deepEqual(result, {
     x1: 340,
-    y1: 520,
+    y1: 400,
     x2: 60,
-    y2: 520,
+    y2: 400,
     preset: 'left',
     durationMs: 300,
     effectiveDurationMs: 300,

src/core/scroll-gesture.ts

@@ -109,7 +109,8 @@ export function buildSwipePresetGesturePlan(
   options: { platform?: string; marginPx?: number } = {},
 ): SwipePresetGesturePlan {
   const marginPx = options.marginPx ?? 8;
-  const horizontalLanePercent = 65;
+  // Mid-screen keeps in-page swipes on visible content; lower lanes can land in blank pager space.
+  const horizontalLanePercent = 50;
   const inPageStartPercent = 85;
   const inPageEndPercent = 15;
   const [startPercent, endPercent, yPercent] =