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/AnnouncementBar.wrn

@@ -234,9 +234,7 @@ badge: string = ""
       background: var(--wrn-color-surface-raised);
       border: 1px solid var(--wrn-color-border);
       border-radius: 1.25rem;
-      box-shadow:
-        0 1px 2px rgb(0 0 0 / 0.04),
-        0 12px 32px rgb(0 0 0 / 0.08);
+      box-shadow: var(--wrn-shadow-2);
     }
 
     .wrn-announcement[data-variant="soft"] .wrn-announcement__surface {
@@ -279,9 +277,7 @@ badge: string = ""
           color-mix(in srgb, var(--announcement-accent) 76%, black 24%)
         );
       border-color: color-mix(in srgb, var(--announcement-contrast) 28%, transparent);
-      box-shadow:
-        0 1px 0 color-mix(in srgb, var(--announcement-contrast) 20%, transparent) inset,
-        0 18px 46px color-mix(in srgb, var(--announcement-accent) 30%, transparent);
+      box-shadow: var(--wrn-shadow-2);
     }
 
     .wrn-announcement__accent {