fix raycaster layers, polygon drag, slider undo, and grid events

- Enable EDITOR_LAYER on R3F raycaster for proper hit detection
- Fix polygon editor drag using refs and direct position passing
- Handle pointercancel events and fix pointerId access in polygon editor
- Fix slider undo by reverting to start value before resuming temporal state
- Allow grid:move during camera drag so polygon editor works while panning
- Bump better-auth to ^1.5.2 and turbo to ^2.8.12
- Remove explicit return type on createAuth for better inference

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/editor/components/ui/controls/slider-control.tsx

@@ -147,12 +147,26 @@ export function SliderControl({
         }
         
         setIsDragging(false)
+        const startVal = dragStartValue
+        const finalVal = valueRef.current
+
         setDragStartValue(null)
         setDragMin(null)
         setDragMax(null)
         document.removeEventListener('pointermove', handlePointerMove)
         document.removeEventListener('pointerup', handlePointerUp)
-        useScene.temporal.getState().resume()
+
+        if (startVal !== null && startVal !== finalVal) {
+          // Revert to start value while paused so the undo baseline is clean
+          onChange(startVal)
+          
+          useScene.temporal.getState().resume()
+          
+          // Apply final value while recording
+          onChange(finalVal)
+        } else {
+          useScene.temporal.getState().resume()
+        }
       }
 
       document.addEventListener('pointermove', handlePointerMove)