Slate v2 Op-family Tenth Slice

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

Goal

• Land the next narrow selection helper follow-on in slate: broaden Transforms.select(...) to the next honest Location cut.

Finding

• The docs already described select(...) as taking a Location.
• The package originally only handled Range | null.
• The next honest cut turned into Path | Point | Range | null, still short of broad path/location parity.

Slice

• Add Path | Point | Range | null support to Transforms.select(...).
• Turn Path into the exact current node range.
• Turn Point into a collapsed selection.
• Keep the slice narrow:
  • no full legacy Location parity

Verification

• yarn mocha --require ./config/babel/register.cjs ./packages/slate/test/snapshot-contract.ts
• yarn test:mocha
• yarn workspace slate-react run test
• targeted tsc diagnostics on changed packages/slate files: 0 errors
• targeted yarn exec eslint on changed packages/slate files
• yarn prettier --check on changed slate-v2 files
• pnpm exec prettier --check on changed plate-2 docs