feat: comprehensive frontend polish - UI/UX improvements across all pages

Public Pages:
- Landing page with server/client split and metadata export
- Cart page with ARIA accessibility and loading states
- Checkout page with form accessibility and proper design system
- Contact page with SEO metadata and improved accessibility
- Pricing page with enhanced FAQ accessibility
- Login page with Suspense boundaries and secure patterns

Brand Storefronts:
- Premium loading skeletons for Tuxedo and Indian River Direct
- Branded error boundaries with animations
- Loading.tsx for about, contact, FAQ, stops pages
- Error.tsx for all storefront subpages

Admin Dashboard:
- AdminSidebar: ARIA labels, keyboard navigation, mobile improvements
- DashboardClient: Stats cards, quick actions, usage progress
- Admin layout: Toast provider integration

Admin Orders/Products/Stops:
- Toast notification system with auto-dismiss
- Skeleton loading components (Table, Card, Stats, Form)
- Bulk actions (mark picked up, publish stops)
- Form validation with error styling

Admin Communications:
- AnalyticsDashboard: sparklines, stat cards, engagement badges
- CampaignComposerPage: step wizard, template selection, email preview
- SegmentBuilderPage: empty state, active segment handling
- ContactListPanel: loading skeletons, professional empty states
- MessageLogPanel: stats cards, engagement indicators
- HarvestReachNav: branded tab navigation
- All pages: metadata exports and loading.tsx

Admin Settings:
- SquareSyncSettingsClient: design system colors, save/cancel UX
- ShippingSettingsForm: validation, dirty state tracking
- Integrations page: proper layout with AI and communications sections
- Billing: improved plan comparison, add-on cards
- PaymentSettings: toggle components, validation

Wholesale Portal:
- Portal: loading skeletons, quantity stepper, search/filter
- Login/Register: FormField validation, success states
- Success/Cancel pages: animated checkmarks
- Employee portal: skeletons, empty states, mobile responsive

Water Log:
- FieldClient: loading step, progress indicator, spinner
- AdminClient: loading skeletons
- Admin pages: loading.tsx files

New Components:
- Toast.tsx/ToastContainer.tsx: comprehensive notification system
- Skeleton.tsx: shimmer loading components
- AdminToggle.tsx: consistent toggle/switch
- CommunicationsLoading.tsx: loading skeleton for comms
- ToastExport.ts: exports

CSS Improvements:
- Shimmer animation keyframes
- Toast slide-in animation

Accessibility:
- ARIA labels throughout
- Keyboard navigation
- Focus states
- Semantic HTML
- Screen reader support

src/app/login/loading.tsx

@@ -0,0 +1,59 @@
+import type { Metadata } from "next";
+
+export const metadata: Metadata = {
+  title: "Loading...",
+  description: "Loading...",
+  robots: {
+    index: false,
+    follow: false,
+  },
+};
+
+export default function Loading() {
+  return (
+    <div className="min-h-screen flex items-center justify-center px-6 py-12 bg-gradient-to-br from-stone-50 to-amber-50/30">
+      {/* Background orbs */}
+      <div 
+        className="fixed w-96 h-96 rounded-full pointer-events-none animate-pulse"
+        style={{
+          background: 'radial-gradient(circle, rgba(34, 197, 94, 0.15) 0%, transparent 70%)',
+          top: '10%',
+          left: '10%',
+          filter: 'blur(60px)'
+        }}
+        aria-hidden="true"
+      />
+      
+      {/* Loading card */}
+      <div className="w-full max-w-sm relative">
+        <div className="bg-white/70 backdrop-blur-2xl rounded-[2rem] shadow-lg p-8">
+          {/* Logo skeleton */}
+          <div className="flex justify-center mb-10">
+            <div className="h-20 w-20 rounded-3xl bg-slate-200 animate-pulse" />
+          </div>
+          
+          {/* Text skeleton */}
+          <div className="space-y-3">
+            <div className="h-8 w-32 rounded bg-slate-200 mx-auto animate-pulse" />
+            <div className="h-4 w-24 rounded bg-slate-100 mx-auto animate-pulse" />
+          </div>
+          
+          {/* Form skeleton */}
+          <div className="mt-8 space-y-4">
+            <div className="space-y-2">
+              <div className="h-4 w-16 rounded bg-slate-100 animate-pulse" />
+              <div className="h-12 rounded-xl bg-slate-100 animate-pulse" />
+            </div>
+            <div className="space-y-2">
+              <div className="h-4 w-20 rounded bg-slate-100 animate-pulse" />
+              <div className="h-12 rounded-xl bg-slate-100 animate-pulse" />
+            </div>
+            <div className="h-12 rounded-xl bg-slate-200 animate-pulse" />
+          </div>
+        </div>
+      </div>
+      
+      <span role="status" className="sr-only">Loading login page...</span>
+    </div>
+  );
+}