feat(core): touch-action derivation, native scroll probe, haptics and the gesture host

.changeset/gesture-browser-negotiation.md

@@ -0,0 +1,7 @@
+---
+'@astryxdesign/core': patch
+---
+
+[chore] Internal: touch-action derivation, the native scroll probe and haptics for the gesture system. Not exported from the package entry point; no component uses them yet.
+
+@vjeux

.changeset/gesture-host.md

@@ -0,0 +1,7 @@
+---
+'@astryxdesign/core': patch
+---
+
+[chore] Internal: the gesture system's DOM host (claims, click suppression, the browser's takeover, the pointer behind a contact), serving a mouse, a pen and a finger alike, with no page listener while idle where the primary pointer is fine. Not exported from the package entry point; no component uses it yet.
+
+@vjeux

packages/core/src/gestures/GestureArena.ts

@@ -262,6 +262,41 @@ export class GestureArena {
     });
   }
 
+  /**
+   * A contact began where nothing takes part (plain page content). It is
+   * never tracked and stays the browser's; recognizers already tracking a
+   * gesture hear of it, as of any touch off their hit path.
+   */
+  untrackedBegan(input: TouchBeganInput): void {
+    if (!this.active.some(recognizer => recognizer.numberOfTouches > 0)) {
+      return;
+    }
+    this.run(input.time, () => {
+      const time = this.clampTime(input.time);
+      const touch: GestureTouch = {
+        id: input.id,
+        pointerType: input.pointerType,
+        phase: 'began',
+        x: input.x,
+        y: input.y,
+        time,
+        startX: input.x,
+        startY: input.y,
+        startTime: time,
+        samples: [{x: input.x, y: input.y, time}],
+        target: input.target,
+        scroll: input.scroll ?? null,
+        takenByBrowser: false,
+      };
+      const context = this.context();
+      for (const recognizer of [...this.active]) {
+        if (recognizer.numberOfTouches > 0) {
+          recognizer.deliverBeganElsewhere([touch], context);
+        }
+      }
+    });
+  }
+
   /** Contacts moved. */
   moved(inputs: ReadonlyArray<TouchInput>): void {
     if (inputs.length === 0) {