Drop minimumActivationDistance from drag gesture configuration

Bumps the swiftui-scrollview-interoperable-drag-gesture submodule to
remove the activation-distance gate. The gate returned early before the
scroll-view lock kicked in, letting the inner scroll view rubber-band /
scroll during the slop window. UIPanGestureRecognizer's built-in slop is
sufficient on its own.

Removes the `minimumActivationDistance: 15` argument from both gesture
configurations in RideauHostingView and updates spec.md accordingly.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: muukii

Rideau/Core/RideauHostingView.swift

@@ -121,8 +121,7 @@ final class RideauHostingView: RideauTouchThroughView {
       ignoresScrollView: false,
       targetEdges: .top,
       sticksToEdges: true,
-      edgeActivationMode: .onlyAtGestureStart,
-      minimumActivationDistance: 15
+      edgeActivationMode: .onlyAtGestureStart
     )
   )
 
@@ -220,8 +219,7 @@ final class RideauHostingView: RideauTouchThroughView {
       ignoresScrollView: ignoresScrollView,
       targetEdges: .top,
       sticksToEdges: true,
-      edgeActivationMode: .onlyAtGestureStart,
-      minimumActivationDistance: 15
+      edgeActivationMode: .onlyAtGestureStart
     )
   }
 

Rideau/spec.md

@@ -39,9 +39,10 @@ its valid range. The implementation should follow this spec.
 
 Configuration:
 `edgeActivationMode: .onlyAtGestureStart`, `targetEdges: .top`,
-`sticksToEdges: true`, `minimumActivationDistance: 15`
+`sticksToEdges: true`
 
-- Consume movement smaller than 15 pt and do not forward it to Rideau.
+- Rely on `UIPanGestureRecognizer`'s built-in recognition slop only; do not
+  apply an additional activation distance on top.
 - While `isScrollLockEnabled == true`, fully lock the inner scroll view and send
   all translation to the outer drag.
 - While `isScrollLockEnabled == false`, activate the outer drag only if the
@@ -102,12 +103,13 @@ ownership is decided by the submodule using `.onlyAtGestureStart`.
 - `targetEdges: .top`. No coordination is performed for the bottom edge.
 - Horizontal scrolling should always remain free and must not be locked.
 
-### 3.4 The 15 pt Gate
+### 3.4 Activation Slop
 
-- The 15 pt threshold is owned entirely by the submodule through
-  `minimumActivationDistance: 15`.
-- Rideau should not apply its own additional gate. Once `onChange` fires,
-  Rideau can assume the user has already moved at least 15 pt.
+- Recognition slop is delegated to `UIPanGestureRecognizer`'s built-in
+  threshold. The submodule does not add an additional activation distance,
+  because doing so would let the inner scroll view rubber-band/scroll while
+  the outer drag is still gated.
+- Rideau should not apply its own gate either.
 
 ## 4. Snap Resolution on Gesture End
 
@@ -174,7 +176,6 @@ ownership is decided by the submodule using `.onlyAtGestureStart`.
 - dynamic switching of `isScrollLockEnabled`
 - configurable `targetEdges`
 - `edgeActivationMode: .onlyAtGestureStart`
-- configurable `minimumActivationDistance`
 - deceleration cancellation when locking and unlocking
 - scroll-indicator hiding while locked