chore: scaffold monorepo and migrate uhd_web design system (W0-A)

- pnpm workspace: apps/{web,server}, packages/{contracts,db,domain,adapters,tasks,agent,testkit}
- server: Hono + zod-openapi, API Key auth with scopes, redacting pino logger, SSE event bus with replay, worker heartbeat
- db: Kysely + pg, file migrator, 0001_init (settings/api_key/audit_event/outbox_event)
- web: React Router 7 SPA console shell with 12 workspace placeholders, uhd_web tokens/ui/guard scripts
- docs: ADR-001 (Node over Deno), dev runbook, design system rules

Co-Authored-By: Claude Fable 5.1 <[email protected]>

apps/web/app/components/ui/sonner.tsx

@@ -0,0 +1,36 @@
+import { CircleCheckIcon, InfoIcon, Loader2Icon, OctagonXIcon, TriangleAlertIcon } from "lucide-react";
+import { useTheme } from "next-themes";
+import { Toaster as Sonner, type ToasterProps } from "sonner";
+
+const Toaster = ({ ...props }: ToasterProps) => {
+  const { theme = "system" } = useTheme();
+
+  return (
+    <Sonner
+      theme={theme as ToasterProps["theme"]}
+      className="toaster group"
+      icons={{
+        success: <CircleCheckIcon className="size-4" />,
+        info: <InfoIcon className="size-4" />,
+        warning: <TriangleAlertIcon className="size-4" />,
+        error: <OctagonXIcon className="size-4" />,
+        loading: <Loader2Icon className="size-4 animate-spin" />,
+      }}
+      style={
+        {
+          "--normal-bg": "var(--popover)",
+          "--normal-text": "var(--popover-foreground)",
+          "--normal-border": "var(--border)",
+          "--border-radius": "var(--radius)",
+          pointerEvents: "none",
+        } as React.CSSProperties
+      }
+      toastOptions={{
+        style: { pointerEvents: "auto" },
+      }}
+      {...props}
+    />
+  );
+};
+
+export { Toaster };