feat(branding): wire per-port branding through every transactional email + auth shell (R2-H15)

Multi-tenant branding admin (/admin/branding) was saving 5 settings
that no code read — every port's emails shipped Port Nimara's logo
and color regardless. Now wired end-to-end:

New shared infrastructure:
- src/lib/email/shell.ts — renderShell() + brandingPrimaryColor()
  helpers; takes BrandingShell { logoUrl, primaryColor,
  emailHeaderHtml, emailFooterHtml }, falls back to Port Nimara
  defaults when null.
- src/lib/email/branding-resolver.ts — getBrandingShell(portId)
  thin wrapper over getPortBrandingConfig() that returns null on
  error / missing portId so senders never break on misconfig.

All 6 transactional templates refactored to use renderShell + the
shared accent color; portName now flows through every template
(crm-invite, portal activation/reset, both inquiries, both
residential templates, notification digest).

All 6 senders pass branding via getBrandingShell:
- portal-auth.service.ts (activation + reset)
- crm-invite.service.ts (resend path; create-invite has no portId
  yet so falls through to defaults)
- email worker (inquiry confirmation + sales notification)
- residential-inquiries route (client confirmation + sales alert)
- notification-digest.service.ts (digest)

BrandedAuthShell takes an optional `branding` prop with logoUrl +
appName (parent page server-fetches via getPortBrandingConfig).
Defaults to Port Nimara if omitted, so single-tenant deployments
are unaffected.

1175/1175 vitest passing.

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

src/app/api/public/residential-inquiries/route.ts

@@ -12,6 +12,7 @@ import {
   residentialSalesAlert,
 } from '@/lib/email/templates/residential-inquiry';
 import { resolveSubject } from '@/lib/email/resolve-subject';
+import { getBrandingShell } from '@/lib/email/branding-resolver';
 import { env } from '@/lib/env';
 import { errorResponse, RateLimitError, ValidationError } from '@/lib/errors';
 import { logger } from '@/lib/logger';
@@ -141,18 +142,22 @@ async function sendResidentialNotifications(args: {
 }): Promise<void> {
   const { portId, data, crmDeepLink } = args;
 
+  const branding = await getBrandingShell(portId);
   // Client confirmation
-  const confirmation = residentialClientConfirmation({
-    firstName: data.firstName,
-    contactEmail: 'sales@portnimara.com',
-  });
+  const confirmation = residentialClientConfirmation(
+    {
+      firstName: data.firstName,
+      contactEmail: 'sales@portnimara.com',
+    },
+    { branding },
+  );
   const confirmationSubject = await resolveSubject({
     key: 'residential_inquiry_client_confirmation',
     portId,
     fallback: confirmation.subject,
     tokens: { portName: 'Port Nimara', recipientName: data.firstName },
   });
-  await sendEmail(data.email, confirmationSubject, confirmation.html);
+  await sendEmail(data.email, confirmationSubject, confirmation.html, undefined, undefined, portId);
 
   // Sales-team alert - pull recipients from system_settings if configured;
   // fall back to the inquiry_contact_email if available.
@@ -181,16 +186,19 @@ async function sendResidentialNotifications(args: {
     return;
   }
 
-  const alert = residentialSalesAlert({
-    fullName: `${data.firstName} ${data.lastName}`.trim(),
-    email: data.email,
-    phone: data.phone,
-    placeOfResidence: data.placeOfResidence,
-    preferredContactMethod: data.preferredContactMethod,
-    notes: data.notes,
-    preferences: data.preferences,
-    crmDeepLink,
-  });
+  const alert = residentialSalesAlert(
+    {
+      fullName: `${data.firstName} ${data.lastName}`.trim(),
+      email: data.email,
+      phone: data.phone,
+      placeOfResidence: data.placeOfResidence,
+      preferredContactMethod: data.preferredContactMethod,
+      notes: data.notes,
+      preferences: data.preferences,
+      crmDeepLink,
+    },
+    { branding },
+  );
   const alertSubject = await resolveSubject({
     key: 'residential_inquiry_sales_alert',
     portId,