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/tenants/route.ts

@@ -0,0 +1,90 @@
+import { NextResponse } from "next/server"
+import { and, desc, eq, sql } from "drizzle-orm"
+import { db } from "@/lib/db"
+import { tenants, units } from "@/lib/db/schema"
+import { getSessionUser } from "@/lib/session"
+import { tenantSchema } from "@/lib/validations"
+import { logActivity } from "@/lib/activity"
+
+export async function GET(request: Request) {
+  const user = await getSessionUser()
+  if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+
+  const { searchParams } = new URL(request.url)
+  const propertyId = searchParams.get("property_id")
+  const status = searchParams.get("status") ?? "active"
+  const page = Math.max(1, parseInt(searchParams.get("page") ?? "1", 10))
+  const limit = Math.min(100, Math.max(1, parseInt(searchParams.get("limit") ?? "50", 10)))
+  const offset = (page - 1) * limit
+
+  const validStatuses = ["active", "inactive", "archived"]
+  if (!validStatuses.includes(status)) {
+    return NextResponse.json({ error: "Invalid status" }, { status: 400 })
+  }
+
+  const where = and(
+    eq(tenants.user_id, user.id),
+    eq(tenants.status, status as typeof tenants.$inferSelect.status),
+    propertyId ? eq(tenants.property_id, propertyId) : undefined
+  )
+
+  const [data, [{ count }]] = await Promise.all([
+    db.query.tenants.findMany({
+      where,
+      with: {
+        unit: { columns: { unit_number: true, rent_amount: true } },
+        property: { columns: { name: true } },
+      },
+      orderBy: desc(tenants.created_at),
+      limit,
+      offset,
+    }),
+    db.select({ count: sql<number>`count(*)::int` }).from(tenants).where(where),
+  ])
+
+  return NextResponse.json({ data, total: count ?? 0, page, limit })
+}
+
+export async function POST(request: Request) {
+  const user = await getSessionUser()
+  if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+
+  const body = await request.json()
+  const parsed = tenantSchema.safeParse(body)
+  if (!parsed.success) return NextResponse.json({ error: parsed.error.flatten() }, { status: 400 })
+
+  const [tenant] = await db
+    .insert(tenants)
+    .values({ ...parsed.data, user_id: user.id })
+    .returning()
+
+  // Mark unit as occupied — verify unit belongs to the submitted property first
+  if (parsed.data.unit_id) {
+    const unit = await db.query.units.findFirst({
+      where: and(
+        eq(units.id, parsed.data.unit_id),
+        eq(units.property_id, parsed.data.property_id),
+        eq(units.user_id, user.id)
+      ),
+      columns: { id: true },
+    })
+
+    if (unit) {
+      await db
+        .update(units)
+        .set({ status: "occupied", current_tenant_id: tenant.id })
+        .where(and(eq(units.id, parsed.data.unit_id), eq(units.user_id, user.id)))
+    }
+  }
+
+  await logActivity({
+    userId: user.id,
+    type: "tenant_added",
+    title: `New tenant added: ${parsed.data.first_name} ${parsed.data.last_name}`,
+    description: parsed.data.email ?? undefined,
+    entityType: "tenant",
+    entityId: tenant.id,
+  })
+
+  return NextResponse.json(tenant, { status: 201 })
+}