Consolidate audit-fixes branch: webhooks, integrations, and deploy hardening

Batch commit of the pending working tree on security/audit-fixes-2026-07.
Major areas:
- Outbound webhooks / Zapier: schema + signed delivery with retries, public
  v1 API (REST-hook subscribe/unsubscribe), settings UI, cron drain.
- Deploy hardening: email via SMTP2GO (Resend fully removed), verified DB TLS
  (DATABASE_SSL=require + DATABASE_CA), storage fails loud in production when
  Spaces is unconfigured instead of silently using ephemeral disk.
- Integrations & features (concurrent work): accounting (QuickBooks/Xero),
  e-signature (DocuSign/Dropbox Sign), PayPal, geocoding/maps, onboarding,
  expanded legal pages.
- DB migrations 0006–0009.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/api/rent/payment-link/route.ts

@@ -4,15 +4,20 @@ import { db } from "@/lib/db"
 import { rent_payments } from "@/lib/db/schema"
 import { getSessionUser } from "@/lib/session"
 import { createRentPaymentLink } from "@/lib/stripe/payment-links"
+import { getAccountContext } from "@/lib/account"
 
 export async function POST(request: Request) {
   const user = await getSessionUser()
   if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
 
+  const ctx = await getAccountContext(user.id)
+  const ownerId = ctx.ownerId
+  if (!ctx.canWrite) return NextResponse.json({ error: "Forbidden" }, { status: 403 })
+
   const { payment_id } = await request.json() as { payment_id: string }
 
   const payment = await db.query.rent_payments.findFirst({
-    where: and(eq(rent_payments.id, payment_id), eq(rent_payments.user_id, user.id)),
+    where: and(eq(rent_payments.id, payment_id), eq(rent_payments.user_id, ownerId)),
     with: {
       tenant: { columns: { first_name: true, last_name: true } },
       property: { columns: { name: true } },
@@ -35,7 +40,7 @@ export async function POST(request: Request) {
   await db
     .update(rent_payments)
     .set({ stripe_payment_link_id: link.id })
-    .where(and(eq(rent_payments.id, payment_id), eq(rent_payments.user_id, user.id)))
+    .where(and(eq(rent_payments.id, payment_id), eq(rent_payments.user_id, ownerId)))
 
   return NextResponse.json({ url: link.url })
 }