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/generate/route.ts

@@ -3,11 +3,16 @@ import { and, eq } from "drizzle-orm"
 import { db } from "@/lib/db"
 import { leases, rent_payments } from "@/lib/db/schema"
 import { getSessionUser } from "@/lib/session"
+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 { year, month } = await request.json() as { year: number; month: number }
   if (!year || month === undefined) return NextResponse.json({ error: "year and month required" }, { status: 400 })
 
@@ -21,7 +26,7 @@ export async function POST(request: Request) {
       rent_amount: leases.rent_amount,
     })
     .from(leases)
-    .where(and(eq(leases.user_id, user.id), eq(leases.status, "active")))
+    .where(and(eq(leases.user_id, ownerId), eq(leases.status, "active")))
 
   if (!activeLeases.length) return NextResponse.json({ created: 0, skipped: 0 })
 
@@ -33,14 +38,14 @@ export async function POST(request: Request) {
   const existing = await db
     .select({ tenant_id: rent_payments.tenant_id })
     .from(rent_payments)
-    .where(and(eq(rent_payments.user_id, user.id), eq(rent_payments.due_date, due_date)))
+    .where(and(eq(rent_payments.user_id, ownerId), eq(rent_payments.due_date, due_date)))
 
   const existingTenantIds = new Set(existing.map((p) => p.tenant_id))
 
   const toInsert = activeLeases
     .filter((l) => !existingTenantIds.has(l.tenant_id))
     .map((l) => ({
-      user_id:     user.id,
+      user_id:     ownerId,
       tenant_id:   l.tenant_id,
       property_id: l.property_id,
       unit_id:     l.unit_id ?? null,