* Preserve rich Markdown viewport through bare focus returns
* Retire viewport ownership on editor remount
* Complete no-op navigation and body Tab coverage
* Keep patch metadata keys separate from dependency snapshots
* Retire the viewport before root detach callbacks
* Give the engine writer fixture its native selection
* Keep native focus navigation current in Markdown
* fix: leave smooth Markdown scrolling to native focus cancellation
* Cover focus wrapper removal and routed Markdown writers
* Type the viewport scroll spy and mark the focus-recovery wait as deliberate
* Scope Markdown viewport wheel and touch guards to the editor scroller
