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>

changes/defaults-views-templates.md

@@ -53,6 +53,28 @@ The runtime is a UI framework, not only a template engine:
 - importing `ludic.ui/render3d.ludic` installs the backend, and atlases take rows;
 - hooks for the program's language, sounds and clock.
 
+What a game's screens found missing, now in `ludic.ui`:
+- `<input type="number" min max step>`: typed digits, Enter or leaving it commits them clamped, the
+  arrows step it;
+- `<input type="key">` listens for any key (Tab and the arrows included) once Enter or a click starts
+  it; Esc stops it, Backspace clears it, `shown` names the value, and `ui_capturing()` tells the host;
+- `note="..."` under any control's label (`.ui-note`); a range's `decimals`, `format="percent"` and
+  `unit`; a track laid out as a row, with the range's fill as tall as it;
+- popovers anchored beside an element (`anchor="id"`, or a bare `anchor` for the element before it,
+  `placement`), flipped to the other side and kept on the screen;
+- `flex-shrink` (a scroll box in a column takes the room its siblings leave), `flex: grow shrink`,
+  `order`, and text in a row wrapping in the room its siblings leave;
+- `calc()` over px, %, em, rem, vw, vh and `var()`; `width: 0` and `height: 0` mean 0;
+- `text-shadow`; tooltips of several lines; `ui_opacity()` for a native's draw;
+- `border-image` drawn as painted with no background colour, tinted by one, and not at all under
+  `transparent`; a picture file drawn untinted (an atlas cell still takes `color`);
+- the render3d backend loads a picture again when its file changes (`ui_image_reload`), draws a path
+  with a drive letter as a path, and slices a nine-slice by its texture's own width and height;
+- a component root that is itself a component takes every user's class, style and id, and the
+  sheets that style it are weighed together by specificity;
+- a component's event may be called `set`; a `string` prop given a number reads it as text; two
+  components of one name are an error naming both files.
+
 render3d gains `tex_width` / `tex_height`, and the XML reader keeps text runs among elements in
 order (`mixed`).