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/paypal/checkout/route.ts

@@ -0,0 +1,73 @@
+import { NextResponse } from "next/server"
+import { eq } from "drizzle-orm"
+import { db } from "@/lib/db"
+import { profiles } from "@/lib/db/schema"
+import { getSessionUser } from "@/lib/session"
+import { paypalConfigured } from "@/lib/paypal/client"
+import { getPaypalPlanId } from "@/lib/paypal/plans"
+import { createSubscription, createOrder } from "@/lib/paypal/checkout"
+import { PLAN_AMOUNTS } from "@/lib/stripe/plans"
+
+const RECURRING = new Set(["pro", "landlord"])
+
+// Start a PayPal checkout for a plan upgrade and return the approval URL.
+// Recurring plans → Subscriptions API; lifetime → one-time Orders API.
+export async function POST(request: Request) {
+  if (!paypalConfigured()) {
+    return NextResponse.json({ error: "PayPal is not configured" }, { status: 400 })
+  }
+  const user = await getSessionUser()
+  if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+
+  const { plan, interval } = (await request.json().catch(() => ({}))) as {
+    plan?: string
+    interval?: "month" | "year"
+  }
+  if (!plan || (plan !== "lifetime" && !RECURRING.has(plan))) {
+    return NextResponse.json({ error: "Invalid plan" }, { status: 400 })
+  }
+
+  const appUrl = process.env.NEXT_PUBLIC_APP_URL!
+  const cancelUrl = `${appUrl}/settings/billing?canceled=true`
+
+  try {
+    if (plan === "lifetime") {
+      const { approveUrl } = await createOrder({
+        amount: PLAN_AMOUNTS.lifetime,
+        userId: user.id,
+        plan: "lifetime",
+        returnUrl: `${appUrl}/api/paypal/return?type=order`,
+        cancelUrl,
+      })
+      if (!approveUrl) throw new Error("PayPal did not return an approval URL")
+      return NextResponse.json({ url: approveUrl })
+    }
+
+    const billingInterval = interval === "year" ? "year" : "month"
+    const planId = getPaypalPlanId(plan as "pro" | "landlord", billingInterval)
+    if (!planId) {
+      return NextResponse.json({ error: "That plan isn't available on PayPal yet." }, { status: 400 })
+    }
+
+    const profile = await db.query.profiles.findFirst({
+      where: eq(profiles.id, user.id),
+      columns: { email: true },
+    })
+
+    const { approveUrl } = await createSubscription({
+      planId,
+      userId: user.id,
+      plan,
+      email: profile?.email ?? user.email,
+      returnUrl: `${appUrl}/api/paypal/return?type=subscription`,
+      cancelUrl,
+    })
+    if (!approveUrl) throw new Error("PayPal did not return an approval URL")
+    return NextResponse.json({ url: approveUrl })
+  } catch (e) {
+    return NextResponse.json(
+      { error: (e as Error).message || "PayPal checkout failed" },
+      { status: 502 }
+    )
+  }
+}