Adds `{ silent: true }` on highlight/selection methods for URL-restore
flows that shouldn't fire change callbacks. Adds array variants and an
`{ exclusive: true }` "focus this branch" option to expandNodes /
expandAll, plus a `{ noEmit: true }` batching option across all four
expand/collapse methods. Two new demo pages.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>