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>

lib/webhooks/events.ts

@@ -0,0 +1,68 @@
+// ============================================================================
+// Webhook event catalog.
+//
+// The single source of truth for the outbound-webhook / Zapier integration.
+// Every event a landlord can subscribe to is declared here. `emitWebhookEvent`
+// (see ./emit) fans an event out to all of an account's endpoints that either
+// subscribe to the event id or subscribe to everything (empty `events` array).
+//
+// This module is intentionally dependency-free (no `crypto`, no db) so it can be
+// imported from client components (e.g. the settings form) and shared schemas.
+// ============================================================================
+
+export const WEBHOOK_EVENTS = [
+  {
+    id: "property.created",
+    label: "Property created",
+    description: "A property was added to the portfolio.",
+  },
+  {
+    id: "tenant.created",
+    label: "Tenant created",
+    description: "A new tenant was added.",
+  },
+  {
+    id: "maintenance.created",
+    label: "Maintenance request opened",
+    description: "A maintenance request was submitted (dashboard, API, or tenant portal).",
+  },
+  {
+    id: "maintenance.updated",
+    label: "Maintenance status changed",
+    description: "A maintenance request moved to a new status (e.g. resolved).",
+  },
+  {
+    id: "payment.recorded",
+    label: "Payment recorded",
+    description: "A rent payment record was created.",
+  },
+  {
+    id: "payment.paid",
+    label: "Payment marked paid",
+    description: "A rent payment was marked as paid.",
+  },
+  {
+    id: "lease.created",
+    label: "Lease created",
+    description: "A lease was created for a tenant.",
+  },
+] as const
+
+export type WebhookEvent = (typeof WEBHOOK_EVENTS)[number]["id"]
+
+/** All valid event ids, plus the reserved `ping` used by the "Send test" button. */
+export const WEBHOOK_EVENT_IDS = WEBHOOK_EVENTS.map((e) => e.id) as WebhookEvent[]
+
+export const PING_EVENT = "ping" as const
+
+export function isWebhookEvent(value: unknown): value is WebhookEvent {
+  return typeof value === "string" && WEBHOOK_EVENT_IDS.includes(value as WebhookEvent)
+}
+
+/** The JSON envelope every webhook POST body uses. */
+export type WebhookEnvelope = {
+  id: string
+  event: WebhookEvent | typeof PING_EVENT
+  created_at: string
+  data: Record<string, unknown>
+}