feat: smooth view transitions, no skeleton flash

User pain point: skeleton loading.tsx files made the app feel like
a sequence of page reloads, exposing backend latency. Replaced with
a single 1px shimmer bar + crossfade via React's <ViewTransition>.

Changes:
- Enable experimental.viewTransition in next.config.ts
- Add SmoothViewTransition wrapper (ViewTransition name=page-content)
- Add LoadingFade component: thin animated bar instead of skeleton
- Add RouteAnnouncer for a11y (screen readers + focus reset)
- Add ::view-transition-old/new CSS for the crossfade (220ms, no
  jarring slide, respects prefers-reduced-motion)
- Wrap admin/tuxedo/IRD layout children in SmoothViewTransition
  (sidebar/header/footer stay mounted; only the body fades)
- Replace 19 skeleton loading.tsx files with the fade component

Result: navigation now feels like a single app, not a series of
preload-and-render events. The user never sees a 'skeleton of the
page they're about to load.'

src/app/indian-river-direct/about/loading.tsx

@@ -1,40 +1,6 @@
-"use client";
-
-import { motion } from "framer-motion";
+import { LoadingFade } from "@/components/transitions/LoadingFade";
 
+/** Subtle navigation indicator — see LoadingFade for rationale. */
 export default function Loading() {
-  return (
-    <div className="min-h-screen bg-stone-50">
-      <div className="mx-auto max-w-4xl px-6 py-20">
-        {/* Hero skeleton */}
-        <div className="mb-20 animate-pulse text-center">
-          <div className="h-3 w-24 rounded bg-blue-100 mx-auto mb-5" />
-          <div className="h-20 w-full max-w-xl mx-auto rounded-lg bg-blue-50 mb-5" />
-          <div className="h-8 w-full max-w-2xl mx-auto rounded bg-blue-50" />
-        </div>
-
-        {/* Content sections skeleton */}
-        <div className="space-y-20">
-          {[0, 1, 2].map((i) => (
-            <motion.div
-              key={i}
-              initial={{ opacity: 0, y: 20 }}
-              animate={{ opacity: 1, y: 0 }}
-              transition={{ delay: i * 0.1 }}
-              className="grid md:grid-cols-2 gap-12 items-center"
-            >
-              <div className="animate-pulse space-y-4">
-                <div className="h-4 w-20 rounded bg-blue-100" />
-                <div className="h-8 w-3/4 rounded bg-stone-200" />
-                <div className="h-4 w-full rounded bg-stone-100" />
-                <div className="h-4 w-full rounded bg-stone-100" />
-                <div className="h-4 w-2/3 rounded bg-stone-100" />
-              </div>
-              <div className="h-64 rounded-3xl bg-gradient-to-br from-blue-50 to-white border-2 border-blue-100" />
-            </motion.div>
-          ))}
-        </div>
-      </div>
-    </div>
-  );
-}
+  return <LoadingFade />;
+}