Phase 3a: shadcn init + Home/Case List view

Initialize shadcn/ui (radix-nova preset) and wire its semantic tokens
to the editorial navy/cream/gold palette so primitives inherit the
judicial voice without per-component overrides.

Replace the Phase 2 live-probe with a real dashboard: KPI tiles,
conic-gradient status donut (ported from the vanilla renderHero),
and a TanStack Table cases list with search + sort. Add useCase(n)
hook with 5s staleTime/refetchInterval to replace the old manual
polling loop when Case Detail ships next.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web-ui/src/components/ui/scroll-area.tsx

@@ -0,0 +1,55 @@
+"use client"
+
+import * as React from "react"
+import { ScrollArea as ScrollAreaPrimitive } from "radix-ui"
+
+import { cn } from "@/lib/utils"
+
+function ScrollArea({
+  className,
+  children,
+  ...props
+}: React.ComponentProps<typeof ScrollAreaPrimitive.Root>) {
+  return (
+    <ScrollAreaPrimitive.Root
+      data-slot="scroll-area"
+      className={cn("relative", className)}
+      {...props}
+    >
+      <ScrollAreaPrimitive.Viewport
+        data-slot="scroll-area-viewport"
+        className="size-full rounded-[inherit] transition-[color,box-shadow] outline-none focus-visible:ring-[3px] focus-visible:ring-ring/50 focus-visible:outline-1"
+      >
+        {children}
+      </ScrollAreaPrimitive.Viewport>
+      <ScrollBar />
+      <ScrollAreaPrimitive.Corner />
+    </ScrollAreaPrimitive.Root>
+  )
+}
+
+function ScrollBar({
+  className,
+  orientation = "vertical",
+  ...props
+}: React.ComponentProps<typeof ScrollAreaPrimitive.ScrollAreaScrollbar>) {
+  return (
+    <ScrollAreaPrimitive.ScrollAreaScrollbar
+      data-slot="scroll-area-scrollbar"
+      data-orientation={orientation}
+      orientation={orientation}
+      className={cn(
+        "flex touch-none p-px transition-colors select-none data-horizontal:h-2.5 data-horizontal:flex-col data-horizontal:border-t data-horizontal:border-t-transparent data-vertical:h-full data-vertical:w-2.5 data-vertical:border-s data-vertical:border-s-transparent",
+        className
+      )}
+      {...props}
+    >
+      <ScrollAreaPrimitive.ScrollAreaThumb
+        data-slot="scroll-area-thumb"
+        className="relative flex-1 rounded-full bg-border"
+      />
+    </ScrollAreaPrimitive.ScrollAreaScrollbar>
+  )
+}
+
+export { ScrollArea, ScrollBar }