ui-layout.md named the arrangement's owners but nothing knew which elements exist, so a
view switch could silently take a running session's tracker reset away: docs/ui-elements.json
now states all 195 by region, pane and view, ui/elements.py loads it, and
tools/ui_elements_dump.py drafts it.
Verified: apps/studio 393 items (13 new) and ui_check 600/0, autocal 358, shared 390 with its
2 known wall-clock failures, lint and doc gates clean; a removed element, a renamed
objectName and a new named widget each fail the suite.
ykcheungab