Fix: Use OAuth authorize flow, show login prompt instead of auto-redirect

app/page.tsx

@@ -1,29 +1,47 @@
 'use client'
 
-import { useEffect } from 'react'
-import { useRouter } from 'next/navigation'
 import { useAuth } from '@/lib/auth/context'
-import { listSites } from '@/lib/api/sites'
-import type { Site } from '@/lib/api/sites'
+import { initiateOAuthFlow } from '@/lib/api/oauth'
 import LoadingOverlay from '@/components/LoadingOverlay'
 import SiteList from '@/components/sites/SiteList'
 
 export default function HomePage() {
   const { user, loading } = useAuth()
-  const router = useRouter()
-
-  useEffect(() => {
-    if (!loading && !user) {
-      router.push('/login')
-    }
-  }, [user, loading, router])
 
   if (loading) {
     return <LoadingOverlay logoSrc="/ciphera_icon_no_margins.png" title="Ciphera Analytics" />
   }
 
   if (!user) {
-    return null
+    return (
+      <div className="container mx-auto px-4 py-8">
+        <div className="max-w-2xl mx-auto text-center py-16">
+          <h1 className="text-4xl font-bold text-neutral-900 dark:text-white mb-4">
+            Welcome to Ciphera Analytics
+          </h1>
+          <p className="text-lg text-neutral-600 dark:text-neutral-400 mb-8">
+            Privacy-first web analytics. No cookies, no tracking. GDPR compliant.
+          </p>
+          <div className="flex gap-4 justify-center">
+            <button
+              onClick={() => initiateOAuthFlow()}
+              className="btn-primary"
+            >
+              Sign In
+            </button>
+            <button
+              onClick={() => {
+                const authUrl = process.env.NEXT_PUBLIC_AUTH_URL || 'https://auth.ciphera.net'
+                window.location.href = `${authUrl}/signup?client_id=analytics-app&redirect_uri=${encodeURIComponent((process.env.NEXT_PUBLIC_APP_URL || window.location.origin) + '/auth/callback')}&response_type=code`
+              }}
+              className="btn-secondary"
+            >
+              Sign Up
+            </button>
+          </div>
+        </div>
+      </div>
+    )
   }
 
   return (