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>

examples/component-showcase/scripts/generate-showcase.mjs

@@ -283,7 +283,7 @@ function defaultValue(prop) {
 function sampleValue(prop, component, variation) {
   const name = prop.name.toLowerCase();
   const curated = {
-    ChatBubble: { title:"", description:"", showMetadata:true, showAvatars:false, items:[{text:"Hi Maya, is the new dashboard ready to review?",direction:"incoming",timestamp:"10:24"},{text:"Yes! I have shared the latest version with you.",direction:"outgoing",timestamp:"10:25",status:"Delivered"},{text:"Thanks, I will take a look this afternoon.",direction:"incoming",timestamp:"10:26"}] },
+    ChatBubble: { title:"", description:"", showMetadata:true, showAvatars:false, items:[{text:"Hi Maya, is the new dashboard ready to review?",direction:"incoming",timestamp:"10:24"},{text:"Yes! I have shared the latest version with you.",direction:"outgoing",timestamp:"10:25",receipt:"read"},{text:"Thanks, I will take a look this afternoon.",direction:"incoming",timestamp:"10:26"},{text:"Great. The release notes are attached too.",direction:"outgoing",timestamp:"10:27",receipt:"delivered"},{text:"One more screenshot coming up.",direction:"outgoing",timestamp:"10:28",receipt:"sent"},{text:"Uploading the final export now.",direction:"outgoing",timestamp:"10:29",receipt:"sending"},{text:"Here is the invoice PDF.",direction:"outgoing",timestamp:"10:30",receipt:"failed",status:"Not delivered",actionLabel:"Retry"}] },
     FileUploadProgress: { label:"Upload progress",fileName:"brand-guidelines.pdf",fileSize:"4.8 MB",uploadedSize:variation === 0 ? "2.4 MB" : "",value:variation === 2 ? 100 : 50,status:["uploading","error","complete"][variation % 3] },
     ListGroup: {title:"Workspace",value:"inbox",items:[{value:"inbox",label:"Inbox",description:"Messages that need your attention",icon:"icon-[lucide--inbox]",badge:"8"},{value:"projects",label:"Projects",description:"Your team's active work",icon:"icon-[lucide--folder]"},{value:"archive",label:"Archive",description:"Completed conversations",icon:"icon-[lucide--archive]"}]},
     Rating: {title:"How was your experience?",value:variation === 1 ? 3 : 4,readonly:variation === 2},