feat(ui): component redesign pass and fixes, release ui 0.8.87

Redesign
- Shared field foundation rules (duplicated across 15 form components and
  emitted globally) are now identical everywhere, so later copies no longer
  silently override earlier redesigns.
- Drawn checkbox and radio controls, white switch thumbs (the thumb was the
  text colour, a black blob in light mode), recessed field wells, keycap
  actions in Modal, Drawer, Popover, Toaster, Pagination, Stepper, DataTable.
- Menus (Dropdown, ContextMenu, Popover, Select dropdown, Navbar panels) share
  one flat raised panel with neutral hover rows and mono section labels.
- Alerts with an accent rail and icon chip; card headers without the grey
  band; accordion, collapse, list, list group, timeline, stats, metrics,
  chat, skeleton, avatar group, clipboard, splitter, section, sidebar,
  navbar and upload progress restyled.
- Chart rebuilt: nice y-axis ticks, gridlines, rounded bars, line and area
  modes, hover tooltips, hidden series leave the scale.

Fixes
- Checkbox and radio labels toggle their input again (empty for="" broke it).
- TimePicker kept every clicked time pressed; only the chosen hour and
  minute are pressed now, and nothing is pressed before a value exists.
- ColorPicker hex readout now follows the picked colour.
- Disabled FileInput no longer shows the native file-input text.
- Date and time panels float instead of pushing content.
- ContextMenu opened at the pointer closes on scroll.
- Drawer left/top/bottom placements slide from their own edge again.
- Image-only Card no longer renders an empty body strip.
- Timeline supports item.time, current/upcoming states, sizes and
  compact/alternate variants; showcase demos use distinct variants.
- ChatBubble: delivery receipts (sending/sent/delivered/read/failed/error)
  and meta aligned to its bubble.

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

packages/ui/components/SplitHero.wrn

@@ -268,14 +268,13 @@ component SplitHero {
     .wrn-split-hero[data-variant="soft"] {
       background:
         radial-gradient(circle at 84% 18%, color-mix(in srgb, var(--split-accent) 16%, transparent), transparent 30%),
-        linear-gradient(135deg, var(--split-accent-soft), transparent 64%),
         var(--wrn-color-background);
     }
 
     .wrn-split-hero[data-variant="raised"] {
       background: var(--wrn-color-surface-raised);
       border-block: 1px solid var(--split-border);
-      box-shadow: 0 22px 70px color-mix(in srgb, black 14%, transparent);
+      box-shadow: var(--wrn-shadow-3);
     }
 
     .wrn-split-hero[data-variant="outline"] {
@@ -635,13 +634,10 @@ component SplitHero {
     .wrn-split-hero__visual {
       overflow: hidden;
       background:
-        linear-gradient(145deg, color-mix(in srgb, var(--split-accent) 7%, transparent), transparent 58%),
         var(--wrn-color-surface-raised);
       border: 1px solid var(--split-border);
       border-radius: 1.5rem;
-      box-shadow:
-        0 1px 0 color-mix(in srgb, white 5%, transparent) inset,
-        0 30px 76px color-mix(in srgb, black 18%, transparent);
+      box-shadow: var(--wrn-highlight-edge, none), var(--wrn-shadow-3);
     }
 
     .wrn-split-hero[data-visual-style="plain"] .wrn-split-hero__visual {
@@ -654,7 +650,6 @@ component SplitHero {
 
     .wrn-split-hero[data-visual-style="soft"] .wrn-split-hero__visual {
       background:
-        linear-gradient(145deg, var(--split-accent-soft), transparent 72%),
         var(--wrn-color-surface-raised);
       box-shadow: none;
     }