[Bug] Auto-keyframe doesn't trigger for position/rotation changes via Plugin API (Motion Beta)

When auto-keyframe mode is enabled in Figma Motion, property changes made through the Plugin API behave inconsistently:

• Stroke width (strokeWeight) — changing this via plugin correctly adds a keyframe at the current playhead position 
• Position (x, y) and Rotation (rotation) — changing these via plugin does NOT add a keyframe, even with auto-keyframe toggled on 

Steps to reproduce:

1. Enable Motion mode and turn on the auto-keyframe toggle
2. Select a node
3. From a plugin, set node.strokeWeight = someValue → keyframe is added automatically
   From the same plugin, set node.x = someValue or node.rotation = someValue → no keyframe added

Expected behavior: All property changes made via the Plugin API should respect the auto-keyframe toggle, just like changes made through the UI do.

Workaround: Manually call applyManualKeyframeTrack for TRANSLATION_X, TRANSLATION_Y, and ROTATION at the desired time — but this requires knowing the current playhead position, which is also not exposed in the Plugin API (a separate gap worth addressing).