ui: apply interface polish from design article review

- Add global font smoothing (antialiased) to body
- Add tabular-nums to all numeric displays: MetricCard values, Costs page,
  AgentDetail token/cost grids and tables, IssueDetail cost summary,
  Companies page budget display
- Replace markdown image hard border with subtle inset box-shadow overlay
- Replace all animate-ping status dots with calmer animate-pulse across
  AgentDetail, IssueDetail, Agents, sidebar, kanban, issues list, and
  active agents panel

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/components/CompanyRail.tsx

@@ -132,7 +132,7 @@ function SortableCompanyItem({
               {hasLiveAgents && (
                 <span className="pointer-events-none absolute -right-0.5 -top-0.5 z-10">
                   <span className="relative flex h-2.5 w-2.5">
-                    <span className="absolute inline-flex h-full w-full animate-ping rounded-full bg-blue-400 opacity-80" />
+                    <span className="absolute inline-flex h-full w-full animate-pulse rounded-full bg-blue-400 opacity-80" />
                     <span className="relative inline-flex h-2.5 w-2.5 rounded-full bg-blue-500 ring-2 ring-background" />
                   </span>
                 </span>