Initial import: property management SaaS + security hardening + admin dashboard

Property Management Network — Next.js 16 (App Router), Better Auth,
Drizzle ORM over PostgreSQL, Stripe, OpenAI, Resend.

Includes:
- Security hardening: access-control/IDOR fixes, TLS-by-default DB layer,
  constant-time cron auth, strict security headers, atomic AI quota gating,
  HTML/email output encoding, demo-backdoor disabled in production.
- Superadmin dashboard at /admin (overview/MRR, server-paginated users with
  ban/impersonate/plan/delete, billing, platform activity + admin audit log,
  AI usage, system health) via the Better Auth admin plugin.
- Seed/migration utility scripts under scripts/.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/(dashboard)/layout.tsx

@@ -0,0 +1,48 @@
+import { redirect } from "next/navigation"
+import { eq } from "drizzle-orm"
+import { db } from "@/lib/db"
+import { profiles } from "@/lib/db/schema"
+import { getSession } from "@/lib/session"
+import { Sidebar } from "@/components/dashboard/sidebar"
+import { Header } from "@/components/dashboard/header"
+import { CommandPalette } from "@/components/dashboard/command-palette"
+import { PageTransition } from "@/components/dashboard/page-transition"
+import { Breadcrumbs } from "@/components/dashboard/breadcrumbs"
+import { ScrollToTop } from "@/components/ui/scroll-to-top"
+import { ImpersonationBanner } from "@/components/admin/impersonation-banner"
+
+export default async function DashboardLayout({ children }: { children: React.ReactNode }) {
+  const session = await getSession()
+  const user = session?.user
+
+  if (!user) {
+    redirect("/login")
+  }
+
+  const profile = await db.query.profiles.findFirst({
+    where: eq(profiles.id, user.id),
+  })
+
+  // Set by the Better Auth admin plugin while an admin is impersonating.
+  const impersonating = Boolean((session?.session as { impersonatedBy?: string })?.impersonatedBy)
+
+  return (
+    <div className="flex h-screen flex-col bg-[#09090b] overflow-hidden">
+      {impersonating && <ImpersonationBanner label={profile?.email ?? user.email} />}
+      <div className="flex flex-1 overflow-hidden">
+        <Sidebar profile={profile ?? null} />
+        <div className="flex flex-1 flex-col overflow-hidden">
+          <Header />
+          <main id="main-scroll" className="flex-1 overflow-y-auto p-4 sm:p-6">
+            <Breadcrumbs />
+            <PageTransition>
+              {children}
+            </PageTransition>
+          </main>
+        </div>
+        <CommandPalette />
+        <ScrollToTop />
+      </div>
+    </div>
+  )
+}