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/api/notifications/read/route.ts

@@ -0,0 +1,18 @@
+import { NextResponse } from "next/server"
+import { and, eq } from "drizzle-orm"
+import { db } from "@/lib/db"
+import { notifications } from "@/lib/db/schema"
+import { getSessionUser } from "@/lib/session"
+
+// PATCH /api/notifications/read — mark all of the user's notifications as read.
+export async function PATCH() {
+  const user = await getSessionUser()
+  if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+
+  await db
+    .update(notifications)
+    .set({ read: true })
+    .where(and(eq(notifications.user_id, user.id), eq(notifications.read, false)))
+
+  return NextResponse.json({ ok: true })
+}