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/checkout/loading.tsx

@@ -1,16 +1,65 @@
+import type { Metadata } from "next";
+
+export const metadata: Metadata = {
+  title: "Processing...",
+  description: "Loading checkout...",
+  robots: {
+    index: false,
+    follow: false,
+  },
+};
+
 export default function Loading() {
   return (
-    <main className="min-h-screen bg-slate-50 px-6 py-12">
-      <div className="mx-auto max-w-4xl">
-        <div className="animate-pulse space-y-6">
-          <div className="h-8 w-48 rounded bg-slate-200" />
-          <div className="h-12 w-80 rounded bg-slate-200" />
-          <div className="h-4 w-full max-w-xl rounded bg-slate-200" />
-          <div className="mt-8 rounded-2xl bg-white p-8 shadow-sm" />
-          <div className="mt-8 rounded-2xl bg-white p-8 shadow-sm" />
-          <div className="mt-8 rounded-2xl bg-white p-8 shadow-sm" />
+    <div className="min-h-screen bg-gradient-to-br from-stone-50 via-white to-emerald-50/30">
+      <div className="h-20 border-b border-slate-100/50" />
+      
+      <main className="px-6 py-12">
+        <div className="mx-auto grid max-w-6xl gap-8 md:grid-cols-[1fr_400px]">
+          <div>
+            {/* Title skeleton */}
+            <div className="h-10 w-32 rounded-lg bg-slate-200 animate-pulse" />
+            <div className="h-5 w-64 rounded mt-3 bg-slate-100 animate-pulse" />
+            
+            {/* Form skeleton */}
+            <div className="mt-8 space-y-6">
+              <div className="rounded-2xl bg-white p-6 shadow-sm border border-slate-100">
+                <div className="h-6 w-40 rounded bg-slate-100 animate-pulse" />
+                <div className="mt-4 space-y-4">
+                  <div className="space-y-2">
+                    <div className="h-4 w-20 rounded bg-slate-100 animate-pulse" />
+                    <div className="h-12 w-full rounded-xl bg-slate-100 animate-pulse" />
+                  </div>
+                  <div className="space-y-2">
+                    <div className="h-4 w-16 rounded bg-slate-100 animate-pulse" />
+                    <div className="h-12 w-full rounded-xl bg-slate-100 animate-pulse" />
+                  </div>
+                </div>
+              </div>
+              
+              {/* Button skeleton */}
+              <div className="h-14 w-full rounded-xl bg-slate-100 animate-pulse" />
+            </div>
+          </div>
+          
+          {/* Sidebar skeleton */}
+          <aside>
+            <div className="rounded-2xl bg-white p-6 shadow-sm border border-slate-100 sticky top-6">
+              <div className="h-6 w-32 rounded bg-slate-100 animate-pulse" />
+              <div className="mt-4 space-y-3">
+                {[1, 2, 3].map((i) => (
+                  <div key={i} className="flex justify-between">
+                    <div className="h-4 w-32 rounded bg-slate-100 animate-pulse" />
+                    <div className="h-4 w-16 rounded bg-slate-100 animate-pulse" />
+                  </div>
+                ))}
+              </div>
+            </div>
+          </aside>
         </div>
-      </div>
-    </main>
+      </main>
+      
+      <span role="status" className="sr-only">Loading checkout...</span>
+    </div>
   );
 }