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/documents/[id]/route.ts

@@ -4,14 +4,17 @@ import { db } from "@/lib/db"
 import { documents } from "@/lib/db/schema"
 import { getSessionUser } from "@/lib/session"
 import { deleteFile } from "@/lib/storage"
+import { getEffectiveOwnerId, getAccountContext } from "@/lib/account"
 
 export async function GET(_: Request, { params }: { params: Promise<{ id: string }> }) {
   const user = await getSessionUser()
   if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
 
+  const ownerId = await getEffectiveOwnerId(user.id)
+
   const { id } = await params
   const doc = await db.query.documents.findFirst({
-    where: and(eq(documents.id, id), eq(documents.user_id, user.id)),
+    where: and(eq(documents.id, id), eq(documents.user_id, ownerId)),
   })
 
   if (!doc) return NextResponse.json({ error: "Not found" }, { status: 404 })
@@ -25,16 +28,20 @@ export async function DELETE(_: Request, { params }: { params: Promise<{ id: str
   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 { id } = await params
 
   const doc = await db.query.documents.findFirst({
-    where: and(eq(documents.id, id), eq(documents.user_id, user.id)),
+    where: and(eq(documents.id, id), eq(documents.user_id, ownerId)),
     columns: { storage_path: true },
   })
 
   if (!doc) return NextResponse.json({ error: "Not found" }, { status: 404 })
 
-  await db.delete(documents).where(and(eq(documents.id, id), eq(documents.user_id, user.id)))
+  await db.delete(documents).where(and(eq(documents.id, id), eq(documents.user_id, ownerId)))
 
   if (doc.storage_path) {
     await deleteFile(doc.storage_path)