fix(juggler): restore humanized mouse trajectory dropped in FF146 migration (#677)

The FF146 Juggler migration (03c1230) rewrote the sendEvents() helper in
Page.dispatchMouseEvent to batch events via Promise.all and, in doing so,
dropped the Camoufox humanize branch. Since then, with humanize=True a long
page.mouse.move() emitted only the single endpoint mousemove — the native C++
cursor trajectory (MouseTrajectories.hpp / ChromeUtils.camouGetMouseTrajectory)
was never invoked, even though the generator and config plumbing remained.

Reintroduce the trajectory expansion inside the new sendEvents():
- factor the single-event dispatch into a sendOne() helper
- when humanize is enabled, expand a mousemove into the C++-generated
  trajectory, dispatching intermediate points sequentially with a 10ms delay,
  then always finishing exactly on the requested destination so clicks/hover
  still land on target
- restore _lastTrackedPos so each move's trajectory starts from the real
  previous cursor position

Verified against the built v152.0.4-beta.25 binary: humanize=True now emits
~180 intermediate mousemoves ending exactly at the destination (was 2);
normal click/fill/drag and humanized click-to-target are unaffected.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

additions/juggler/protocol/PageHandler.js

@@ -81,6 +81,9 @@ export class PageHandler {
 
     this._isDragging = false;
     this._lastMousePosition = { x: 0, y: 0 };
+    // Camoufox: last position an actual mousemove landed on. Used as the
+    // start point for the humanized cursor trajectory (humanize=True).
+    this._lastTrackedPos = { x: 0, y: 0 };
 
     this._reportedFrameIds = new Set();
     this._networkEventsForUnreportedFrameIds = new Map();
@@ -523,13 +526,14 @@ export class PageHandler {
         await helper.awaitTopic('apz-repaints-flushed');
 
       const watcher = new EventWatcher(this._pageEventSink, types, this._pendingEventWatchers);
-      const promises = [];
-      for (const type of types) {
+      // Dispatch a single synthesized mouse event to the renderer and return a
+      // promise that resolves once the renderer acks it.
+      const sendOne = (eventType, eventX, eventY) => {
         // This dispatches to the renderer synchronously.
         const jugglerEventId = win.windowUtils.jugglerSendMouseEvent(
-          type,
-          x + boundingBox.left,
-          y + boundingBox.top,
+          eventType,
+          eventX + boundingBox.left,
+          eventY + boundingBox.top,
           button,
           clickCount,
           modifiers,
@@ -542,7 +546,33 @@ export class PageHandler {
           win.windowUtils.DEFAULT_MOUSE_POINTER_ID /* pointerIdentifier */,
           false /* disablePointerEvent */
         );
-        promises.push(watcher.ensureEvent(type, eventObject => eventObject.jugglerEventId === jugglerEventId));
+        return watcher.ensureEvent(eventType, eventObject => eventObject.jugglerEventId === jugglerEventId);
+      };
+
+      const promises = [];
+      for (const type of types) {
+        // Camoufox: when humanize is enabled, expand a direct mousemove into a
+        // human-like trajectory of intermediate mousemoves generated in C++
+        // (ChromeUtils.camouGetMouseTrajectory / MouseTrajectories.hpp).
+        if (type === 'mousemove' && ChromeUtils.camouGetBool('humanize', false)) {
+          const trajectory = ChromeUtils.camouGetMouseTrajectory(this._lastTrackedPos.x, this._lastTrackedPos.y, x, y);
+          // Dispatch intermediate points sequentially with a short delay. The
+          // first/last pairs are skipped: the last pair is the exact
+          // destination, which is dispatched explicitly below.
+          for (let i = 2; i < trajectory.length - 2; i += 2) {
+            const currentX = trajectory[i];
+            const currentY = trajectory[i + 1];
+            // Skip movement that is out of bounds
+            if (currentX < 0 || currentY < 0 || currentX > boundingBox.width || currentY > boundingBox.height)
+              continue;
+            await sendOne('mousemove', currentX, currentY);
+            await new Promise(resolve => setTimeout(resolve, 10));
+          }
+          // Always finish exactly on the requested destination.
+          promises.push(sendOne('mousemove', x, y));
+        } else {
+          promises.push(sendOne(type, x, y));
+        }
       }
       await Promise.all(promises);
       await watcher.dispose();
@@ -603,6 +633,9 @@ export class PageHandler {
 
         const watcher = new EventWatcher(this._pageEventSink, ['dragstart', 'juggler-drag-finalized'], this._pendingEventWatchers);
         await sendEvents(['mousemove']);
+        // Camoufox: remember where the cursor landed so the next humanized
+        // move starts its trajectory from the real previous position.
+        this._lastTrackedPos = { x, y };
 
         // The order of events after 'mousemove' is sent:
         // 1. [dragstart] - might or might NOT be emitted