feat(platform): residential module + admin UI + reliability fixes

Residential platform
- New schema: residentialClients, residentialInterests (separate from
  marina/yacht clients) with migration 0010
- Service layer with CRUD + audit + sockets + per-port portal toggle
- v1 + public API routes (/api/v1/residential/*, /api/public/residential-inquiries)
- List + detail pages with inline editing for clients and interests
- Per-user residentialAccess toggle on userPortRoles (migration 0011)
- Permission keys: residential_clients, residential_interests
- Sidebar nav + role form integration
- Smoke spec covering page loads, UI create flow, public endpoint

Admin & shared UI
- Admin → Forms (form templates CRUD) with validators + service
- Notification preferences page (in-app + email per type)
- Email composition + accounts list + threads view
- Branded auth shell shared across CRM + portal auth surfaces
- Inline editing extended to yacht/company/interest detail pages
- InlineTagEditor + per-entity tags endpoints (yachts, companies)
- Notes service polymorphic across clients/interests/yachts/companies
- Client list columns: yachtCount + companyCount badges
- Reservation file-download via presigned URL (replaces stale <a href>)

Route handler refactor
- Extracted yachts/companies/berths reservation handlers to sibling
  handlers.ts files (Next.js 15 route.ts only allows specific exports)

Reliability fixes
- apiFetch double-stringify bug fixed across 13 components
  (apiFetch already JSON.stringifies its body; passing a stringified
  body produced double-encoded JSON which failed zod validation)
- SocketProvider gated behind useSyncExternalStore-based mount check
  to avoid useSession() SSR crashes under React 19 + Next 15
- apiFetch falls back to URL-pathname → port-id resolution when the
  Zustand store hasn't hydrated yet (fresh contexts, e2e tests)
- CRM invite flow (schema, service, route, email, dev script)
- Dashboard route → [portSlug]/dashboard/page.tsx + redirect
- Document the dev-server restart-after-migration gotcha in CLAUDE.md

Tests
- 5-case residential smoke spec
- Integration test updates for new service signatures

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

src/app/(dashboard)/[portSlug]/email/page.tsx

@@ -1,16 +1,47 @@
+'use client';
+
+import { useState } from 'react';
+import { Send } from 'lucide-react';
+
+import { Button } from '@/components/ui/button';
+import { Tabs, TabsList, TabsTrigger, TabsContent } from '@/components/ui/tabs';
+import { EmailAccountsList } from '@/components/email/email-accounts-list';
+import { EmailThreadsList } from '@/components/email/email-threads-list';
+import { ComposeDialog } from '@/components/email/compose-dialog';
+
 export default function EmailPage() {
+  const [tab, setTab] = useState('threads');
+  const [composeOpen, setComposeOpen] = useState(false);
+
   return (
     <div className="space-y-6">
-      <div>
-        <h1 className="text-2xl font-bold text-foreground">Email</h1>
-        <p className="text-muted-foreground">Send and manage client communications</p>
-      </div>
-      <div className="flex flex-col items-center justify-center rounded-lg border border-dashed p-12">
-        <p className="text-lg font-medium text-muted-foreground">Coming in Layer 3</p>
-        <p className="text-sm text-muted-foreground">
-          This feature will be implemented in the next phase.
-        </p>
+      <div className="flex items-start justify-between gap-4">
+        <div>
+          <h1 className="text-2xl font-bold text-foreground">Email</h1>
+          <p className="text-muted-foreground">Send and manage client communications</p>
+        </div>
+        <Button onClick={() => setComposeOpen(true)}>
+          <Send className="h-4 w-4 mr-1.5" />
+          Compose
+        </Button>
       </div>
+
+      <Tabs value={tab} onValueChange={setTab}>
+        <TabsList>
+          <TabsTrigger value="threads">Inbox</TabsTrigger>
+          <TabsTrigger value="accounts">Accounts</TabsTrigger>
+        </TabsList>
+
+        <TabsContent value="threads" className="pt-4">
+          <EmailThreadsList />
+        </TabsContent>
+
+        <TabsContent value="accounts" className="pt-4">
+          <EmailAccountsList />
+        </TabsContent>
+      </Tabs>
+
+      <ComposeDialog open={composeOpen} onOpenChange={setComposeOpen} />
     </div>
   );
 }