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/draw.ludic

@@ -16,7 +16,7 @@ function fr_draw_in(n: UiNode) -> void {
   fr_background(n)
   fr_border(n)
   if n.kind == UI_TEXT { fr_text(n) }
-  if n.kind == UI_IMAGE and ui_be.image != null { ui_be.image(n.src, n.x + n.pl + n.bl, n.y + n.pt + n.bt, n.cw - ly_hin(n), n.ch - ly_vin(n), n.rfg, fr_ga * n.rfg_a) }
+  if n.kind == UI_IMAGE and ui_be.image != null { fr_image(n) }
   let clipped = n.kind == UI_SCROLL and ui_be.clip != null
   if clipped { fr_clip_push(n.x, n.y, n.cw, n.ch) }
   if n.children != null { fr_children(n) }
@@ -24,8 +24,9 @@ function fr_draw_in(n: UiNode) -> void {
   if n.kind == UI_SCROLL { sc_bar(n) }
   if n.outline_w > 0.0 { fr_outline(n) }
 }
-# the shadow, then the background: a nine-slice tinted by the background colour, or the colour
-# (rounded), then a picture over it
+# the shadow, then the background: the colour (rounded), or a border-image's nine-slice - drawn as
+# painted, as CSS draws one, or tinted by a background colour when there is one (so `transparent`,
+# or any colour with no alpha, leaves nothing to see) - then a picture over it
 function fr_background(n: UiNode) -> void {
   if n.sh_c >= 0 { fr_fill(n, n.x + n.sh_x, n.y + n.sh_y, n.sh_c, fr_ga * n.sh_a) }
   if n.bg >= 0 or n.bi_src != "" {
@@ -35,7 +36,7 @@ function fr_background(n: UiNode) -> void {
       c = 16777215
       a = fr_ga
     }
-    fr_fill(n, n.x, n.y, c, a)
+    if a > 0.0 { fr_fill(n, n.x, n.y, c, a) }
   }
   if n.bg_img != "" and ui_be.image != null { ui_be.image(n.bg_img, n.x, n.y, n.cw, n.ch, 16777215, fr_ga) }
 }
@@ -80,23 +81,3 @@ function fr_outline(n: UiNode) -> void {
   }
   fr_frame(n.x - o, n.y - o, n.cw + o * 2.0, n.ch + o * 2.0, n.outline_w, c, a)
 }
-# a text's lines (one, or the wrapped ones), each placed by text-align, the last cut by an ellipsis
-function fr_text(n: UiNode) -> void {
-  let y = n.y + n.pt + n.bt
-  let a = n.rfg_a * fr_ga
-  if n.lines == null {
-    var s = n.text
-    if n.ellipsis { s = ly_ellipsis(s, n.rsize, n.cw - ly_hin(n)) }
-    ui_be.text(fr_line_x(n, s), y, s, n.rsize, n.rfg, a)
-    return
-  }
-  for i in 0 .. len(n.lines) { ui_be.text(fr_line_x(n, n.lines[i]), y + float(i) * n.rsize * 1.25, n.lines[i], n.rsize, n.rfg, a) }
-}
-# where a line starts: text-align within the room the box gives it
-function fr_line_x(n: UiNode, s: string) -> float {
-  let x = n.x + n.pl + n.bl
-  if n.talign == UI_START { return x }
-  let spare = n.cw - ly_hin(n) - ly_text_w(s, n.rsize)
-  if n.talign == UI_CENTER { return x + spare / 2.0 }
-  return x + spare
-}