feat(ui): number and key fields, notes, anchored popovers, text-shadow, and pictures as painted

- <input type="number" min max step>: typed digits replace its value (a minus when min allows one,
  a point when step has a fraction), Enter or leaving the field commits them held between min and
  max, the left and right arrows step it.
- <input type="key">: Enter or a click starts it listening and the next key is its value, Tab, the
  arrows and Enter included; Esc stops it listening, Backspace clears it, `shown` names the value,
  and ui_capturing() tells the host to leave its keys alone (through the frame that ended it).
- note="..." under any control's label (.ui-labels > .ui-label + .ui-note); a range's (or number's)
  value with decimals, format="percent" and a unit.
- A popover with `anchor="id"` (the nearest element of that id) or a bare `anchor` (the element
  before it) sits beside it by `placement` (right, left, bottom, top), its margin the gap, opens to
  the other side where it would leave the screen, and is kept on it.
- A tooltip's title splits into lines at a newline or a written \n.
- text-shadow, inherited, drawn sharp under the text.
- ui_opacity(): the group opacity a native's draw is at.
- border-image is drawn as painted with no background colour, tinted by one, and not at all when
  that colour is transparent (it drew a white nine-slice).
- A picture file is drawn untinted, as a browser draws one; an atlas cell (prefix:name) still takes
  the color around it, and an <img> with its own color is tinted by it.
- The render3d backend loads a picture again when its file changes or appears (a failed load was
  kept for ever), and at once after ui_image_reload(path); takes a path with a drive letter (C:/...)
  as a path rather than an atlas; and slices a nine-slice by its texture's own width and height.
- ui_inputs.ludic and ui_look.ludic; LANGUAGE.md and the changeset say all of it.

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

packages/ludic.ui/focus.ludic

@@ -1,6 +1,6 @@
 # focus.ludic - the keyboard's place: focus moves through the controls in document order (Tab and
 # Shift+Tab, or the arrows), Enter and Space activate what has it, and a pointer press focuses what
-# it presses. A key that is gone from the screen leaves nothing focused.
+# it presses; a key field that is listening has every key to itself. A key that is gone from the screen leaves nothing focused.
 var fc_key: string = ""
 var fc_visible: bool = false    # focus came from the keyboard: :focus-visible, and the ring
 var fc_list: []UiNode = new []UiNode
@@ -28,8 +28,9 @@ function fc_move(step: int) -> void {
 function fc_keys(root: UiNode) -> void {
   fc_list = new []UiNode
   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) }
+  if ct_key_capture(fc_list) { return }
+  if top != null and in_now.escape { ui_fire(top, "close", Value.null()) }
   let i = in_now
   if fc_find() < 0 { fc_autofocus() }
   let at = fc_find()
@@ -39,6 +40,7 @@ function fc_keys(root: UiNode) -> void {
   let horizontal = n != null and ct_takes_arrows(n)
   if i.up or (i.left and not horizontal) { fc_move(-1) }
   if i.down_key or (i.right and not horizontal) { fc_move(1) }
+  ct_num_blur(root)
   if n == null { return }
   if i.enter or (i.space and not ct_takes_space(n)) { ct_activate(n) }
   if horizontal and i.left { ct_step(n, -1) }