Slate v2 Transforms Namespace Recovery

Goal

Restore the legacy transform helper namespace objects as thin public sugar over the current v2 engine.

Completed

• exported:
  • GeneralTransforms
  • NodeTransforms
  • SelectionTransforms
  • TextTransforms
• kept them thin:
  • GeneralTransforms.applyBatch(...) is one outer transaction over ordered editor.apply(...) calls
  • GeneralTransforms.transform(...) is direct editor.apply(...) sugar
  • the node/selection/text namespaces delegate to the current editor.* / transform seams
• widened snapshot-contract.ts to prove the namespace exports and behavior
• updated the public transforms docs and package/control docs to include the recovered family

Verification

• yarn test:custom
• yarn lint:typescript