feat: member portal Sprint 5 — onboarding portal experience + restore Thread schema

- Redesign onboarding into a 5-step wizard: welcome → phone → consent → code → done
- Progress bar, human-readable consent scopes (INGEST/ARCHIVE/REPLICATE/DISPLAY) with descriptions
- Resend-code action, back navigation, indigo theme matching member portal
- "Done" step introduces portal features (digests, events, privacy) with CTA
- Onboard page shell: rounded card, policy footer
- Restore Thread model + Message.expiresAt/quotedPlatformMsgId/threadId + RAW/DNC statuses to schema.prisma (wiped by prior reset; matches existing add_hybrid_ai_architecture migration) — unblocks ThreadsModule registration

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/app/onboard/page.tsx

@@ -42,25 +42,27 @@ export default async function OnboardPage({
 
   if (error || !info) {
     return (
-      <div className="max-w-md mx-auto mt-12 p-6 rounded-lg border border-red-200 bg-red-50">
+      <div className="max-w-md mx-auto mt-12 p-6 rounded-2xl border border-red-200 bg-red-50">
         <h1 className="text-lg font-semibold text-red-800">Cannot start onboarding</h1>
-        <p className="text-sm text-red-700">{error ?? 'Unknown error'}</p>
+        <p className="text-sm text-red-700 mt-1">{error ?? 'Unknown error'}</p>
       </div>
     );
   }
 
   return (
-    <div className="max-w-md mx-auto mt-12 p-6 rounded-lg border border-gray-200 bg-white">
-      <h1 className="text-xl font-semibold mb-2">Join {info.groupName}</h1>
-      <p className="text-sm text-gray-600 mb-1">Managed by {info.tenantName}</p>
-      <p className="text-xs text-gray-500 mb-4">
-        Policy version: {info.policyVersion} · Default retention: {info.defaultRetentionDays} days
+    <div className="max-w-md mx-auto mt-12">
+      <div className="p-6 sm:p-7 rounded-2xl border border-gray-200 bg-white shadow-sm">
+        <OnboardingForm
+          token={token}
+          groupName={info.groupName}
+          tenantName={info.tenantName}
+          defaultScopes={info.defaultScopes}
+          defaultRetentionDays={info.defaultRetentionDays}
+        />
+      </div>
+      <p className="text-center text-xs text-gray-400 mt-4">
+        Policy {info.policyVersion} · Your data, your control
       </p>
-      <OnboardingForm
-        token={token}
-        defaultScopes={info.defaultScopes}
-        defaultRetentionDays={info.defaultRetentionDays}
-      />
     </div>
   );
 }