Slate v2 Op-family Sixteenth Slice

Supporting plan. For current queue and roadmap truth, see master-roadmap.md.

Goal

• Land the first honest Transforms.move(...) cut without pretending the full legacy selection-motion family already exists.

Scope

• Start with selection motion only.
• Support distance, reverse, and edge.
• Keep motion within each moved point's current text node.
• Support:
  • default both-edge motion
  • anchor
  • focus
  • start
  • end
• Avoid unit parity and any cross-node cursor walking in this slice.

Phases

• Confirm the narrow move semantics and current selection-helper seams
• Write focused failing tests
• Implement the smallest honest core/API slice
• Sync package/public docs
• Verify the touched package/docs