feat(ui): popovers, tooltips, progress; the render3d backend installs itself; duplicate names caught first

- `popover`: a top layer that keeps the pointer and the keyboard, closed by a press outside or Esc.
- `title` tooltips after half a second's rest, styled by .ui-tooltip.
- `<progress>` and `<meter>`.
- Atlases take rows and number cells, and importing ludic.ui/render3d.ludic is enough to draw with
  render3d.
- The compiler reports two declarations of one name before it type-checks, so a package global
  clashing with a program's reads as that, not as 29 type errors.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.ui/focus.ludic

@@ -27,7 +27,9 @@ function fc_move(step: int) -> void {
 # the keys, after the tree is laid out: moving, then acting on what has the focus
 function fc_keys(root: UiNode) -> void {
   fc_list = new []UiNode
-  fc_collect(root)
+  let top = pp_top(root)
+  if top != null and in_now.escape { ui_fire(top, "close", Value.null()) }
+  if top != null { fc_collect(top) } else { fc_collect(root) }
   let i = in_now
   if fc_find() < 0 { fc_autofocus() }
   let at = fc_find()