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/Kbd.wrn

@@ -26,16 +26,18 @@ component Kbd {
       display: inline-flex;
       align-items: center;
       justify-content: center;
-      min-width: 1.6rem;
-      padding: 0.15rem 0.4rem;
+      min-width: 1.5rem;
+      height: 1.5rem;
+      padding: 0 0.4rem;
       border: 1px solid var(--wrn-color-border);
-      /* The lower edge is what reads as a physical key. */
+      border-bottom-color: var(--wrn-color-border-strong, var(--wrn-color-border));
       border-bottom-width: 2px;
-      border-radius: var(--wrn-radius-sm);
-      background: var(--wrn-color-surface-soft);
-      color: var(--wrn-color-text);
-      font-family: inherit;
-      font-size: 0.78rem;
+      border-radius: 0.375rem;
+      background: linear-gradient(180deg, var(--wrn-color-surface), var(--wrn-color-surface-soft, var(--wrn-color-surface)));
+      box-shadow: var(--wrn-highlight-edge, none), 0 1px 1px rgb(0 0 0 / 0.05);
+      color: var(--wrn-color-text-muted, var(--wrn-color-text));
+      font-family: var(--wrn-font-mono, monospace);
+      font-size: 0.72rem;
       font-weight: 600;
       line-height: 1;
     }