docs: clarify unit, coordinate system, and HID origin for LampInfo.Position and LampArray.BoundingBox

[Copilot]

LampInfo.Position and LampArray.BoundingBox lacked any specification of units, coordinate system handedness, axis orientation, or origin—forcing developers to reverse-engineer scale empirically.

lampinfo_position.md

• Description now explicitly states values are in meters relative to the front-top-left corner of the bounding box
• Property-value section describes each Vector3 axis (X=right, Y=down, Z=away from user)
• New Remarks section covering:
  • Left-handed coordinate system with explicit +X/+Y/+Z directions
  • Origin definition: (0, 0, 0) = front-top-left corner of LampArray.BoundingBox
  • HID provenance: values converted from micrometers (µm ÷ 1,000,000) per the HID LampArray descriptor
• See-also links added for BoundingBox, HID spec, and Dynamic lighting docs

lamparray_boundingbox.md

• Added explicit left-handed coordinate system block with +X/+Y/+Z axis directions (parallel with Position page)
• Added note that extents originate from the HID descriptor in micrometers, converted to meters by the WinRT layer

• Fixes Missing Unit Specification for LampInfo.Position #2539