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>

examples/library/ui_popover_parts/Verbs.ludic

@@ -0,0 +1,6 @@
+# Verbs.ludic - a grid cell that opens a popover of verbs
+component Verbs {
+  state open: bool = false
+  state used: string = "none"
+  state health: int = 30
+}