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/console/page-header.tsx

@@ -0,0 +1,25 @@
+import type { ReactNode } from "react";
+import { cn } from "~/lib/utils";
+
+/** 控制台页面标题:标题 + 一句说明 + 右侧操作区 */
+export function PageHeader({
+  title,
+  description,
+  actions,
+  className,
+}: {
+  title: string;
+  description?: ReactNode;
+  actions?: ReactNode;
+  className?: string;
+}) {
+  return (
+    <div className={cn("mb-6 flex flex-wrap items-end justify-between gap-4", className)}>
+      <div className="min-w-0">
+        <h1 className="text-title-lg font-semibold tracking-tight text-foreground">{title}</h1>
+        {description ? <p className="mt-1 text-body text-muted-foreground">{description}</p> : null}
+      </div>
+      {actions ? <div className="flex shrink-0 items-center gap-2">{actions}</div> : null}
+    </div>
+  );
+}