Move share page redirect logic to ShareProvider

Centralizes the single-section redirect logic in ShareProvider instead of
SharePage, reducing useEffect complexity and preventing children from
rendering during redirect.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/share/ShareProvider.tsx

@@ -1,6 +1,7 @@
 'use client';
 import { Loading } from '@umami/react-zen';
-import { createContext, type ReactNode } from 'react';
+import { usePathname, useRouter } from 'next/navigation';
+import { createContext, type ReactNode, useEffect } from 'react';
 import { useShareTokenQuery } from '@/components/hooks';
 import type { WhiteLabel } from '@/lib/types';
 
@@ -14,14 +15,48 @@ export interface ShareData {
 
 export const ShareContext = createContext<ShareData>(null);
 
+const ALL_SECTION_IDS = [
+  'overview',
+  'events',
+  'sessions',
+  'realtime',
+  'compare',
+  'breakdown',
+  'goals',
+  'funnels',
+  'journeys',
+  'retention',
+  'utm',
+  'revenue',
+  'attribution',
+];
+
 export function ShareProvider({ shareId, children }: { shareId: string; children: ReactNode }) {
   const { share, isLoading, isFetching } = useShareTokenQuery(shareId);
+  const router = useRouter();
+  const pathname = usePathname();
+  const path = pathname.split('/')[3];
+
+  const allowedSections = share?.parameters
+    ? ALL_SECTION_IDS.filter(id => share.parameters[id] !== false)
+    : [];
+
+  const shouldRedirect =
+    allowedSections.length === 1 &&
+    allowedSections[0] !== 'overview' &&
+    (path === undefined || path === '' || path === 'overview');
+
+  useEffect(() => {
+    if (shouldRedirect) {
+      router.replace(`/share/${shareId}/${allowedSections[0]}`);
+    }
+  }, [shouldRedirect, shareId, allowedSections, router]);
 
   if (isFetching && isLoading) {
     return <Loading placement="absolute" />;
   }
 
-  if (!share) {
+  if (!share || shouldRedirect) {
     return null;
   }