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/actions/accounting.ts

@@ -0,0 +1,30 @@
+"use server"
+
+import { revalidatePath } from "next/cache"
+import { getSessionUser } from "@/lib/session"
+import { getAccountContext } from "@/lib/account"
+import { disconnect, syncNow, getProvider, type Provider } from "@/lib/accounting"
+
+async function ownerGuard() {
+  const user = await getSessionUser()
+  if (!user) throw new Error("Unauthorized")
+  const ctx = await getAccountContext(user.id)
+  if (!ctx.isOwner) throw new Error("Only the account owner can manage integrations")
+  return ctx
+}
+
+export async function disconnectAccounting(provider: string) {
+  const ctx = await ownerGuard()
+  if (!getProvider(provider)) throw new Error("Unknown provider")
+  await disconnect(ctx.ownerId, provider as Provider)
+  revalidatePath("/settings/integrations")
+  return { ok: true }
+}
+
+export async function syncAccountingNow(provider: string) {
+  const ctx = await ownerGuard()
+  if (!getProvider(provider)) throw new Error("Unknown provider")
+  const result = await syncNow(ctx.ownerId, provider as Provider)
+  revalidatePath("/settings/integrations")
+  return { ok: true, ...result }
+}