feat(portal): branded auth pages + legacy email styling + dev redirect override

- New PortalAuthShell component: blurred Port Nimara overhead background +
  circular logo + white rounded card, used by /portal/login,
  /portal/activate, /portal/reset-password
- New email/templates/portal-auth.ts: table-based, responsive (max-width
  600px / width 100%), matching the existing legacy inquiry templates;
  replaces the inline templates that lived in portal-auth.service
- EMAIL_REDIRECT_TO env override: when set, sendEmail routes every
  outbound message to that address regardless of recipient and tags the
  subject with "[redirected from <original>]". Dev/test safety net only;
  unset in production
- Portal password minimum length 12 → 9 (service + both API routes +
  client-side form)
- Dev helper script scripts/dev-trigger-portal-invite.ts: seeds a portal
  user against the first port-nimara client and uses EMAIL_REDIRECT_TO
  as the stored email so the tester can sign in with the address that
  received the activation mail

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/portal/portal-auth-shell.tsx

@@ -0,0 +1,27 @@
+const BG_URL = 'https://s3.portnimara.com/images/Overhead_1_blur.png';
+const LOGO_URL =
+  'https://s3.portnimara.com/images/Port%20Nimara%20New%20Logo-Circular%20Frame_250px.png';
+
+export function PortalAuthShell({ children }: { children: React.ReactNode }) {
+  return (
+    <div
+      className="min-h-screen flex items-center justify-center px-4 py-8"
+      style={{
+        backgroundImage: `url('${BG_URL}')`,
+        backgroundSize: 'cover',
+        backgroundPosition: 'center',
+        backgroundColor: '#f2f2f2',
+      }}
+    >
+      <div className="w-full max-w-md">
+        <div className="bg-white rounded-lg shadow-lg p-8">
+          <div className="flex justify-center mb-6">
+            {/* eslint-disable-next-line @next/next/no-img-element */}
+            <img src={LOGO_URL} alt="Port Nimara" className="w-24 h-auto" />
+          </div>
+          {children}
+        </div>
+      </div>
+    </div>
+  );
+}