Update user authentication to correctly track previous email addresses

Replaces `previousEmail` state with a ref (`previousEmailRef`) to accurately track the user's old email address during authentication flow, specifically for handling email change notifications.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: a16cce43-1d93-4e5c-a1e6-6ca90e68cc4f
Replit-Commit-Checkpoint-Type: full_checkpoint

src/hooks/useAuth.tsx

@@ -23,12 +23,12 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
   const [profile, setProfile] = useState<Profile | null>(null);
   const [loading, setLoading] = useState(true);
   const [pendingEmail, setPendingEmail] = useState<string | null>(null);
-  const [previousEmail, setPreviousEmail] = useState<string | null>(null);
   
   // Refs for lifecycle and cleanup management
   const isMountedRef = useRef(true);
   const profileFetchTimeoutRef = useRef<NodeJS.Timeout | null>(null);
   const novuUpdateTimeoutRef = useRef<NodeJS.Timeout | null>(null);
+  const previousEmailRef = useRef<string | null>(null);
 
   const fetchProfile = async (userId: string) => {
     try {
@@ -107,9 +107,9 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
       // Detect confirmed email change: email changed AND no longer pending
       if (
         session?.user &&
-        previousEmail &&
+        previousEmailRef.current &&
         currentEmail &&
-        currentEmail !== previousEmail &&
+        currentEmail !== previousEmailRef.current &&
         !newEmailPending
       ) {
         // Clear any existing Novu update timeout
@@ -118,6 +118,7 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
         }
         
         // Defer Novu update and notifications to avoid blocking auth
+        const oldEmail = previousEmailRef.current;
         novuUpdateTimeoutRef.current = setTimeout(async () => {
           if (!isMountedRef.current) return;
           
@@ -137,7 +138,7 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
               target_user_id: session.user.id,
               action: 'email_change_completed',
               details: {
-                old_email: previousEmail,
+                old_email: oldEmail,
                 new_email: currentEmail,
                 timestamp: new Date().toISOString(),
               },
@@ -149,7 +150,7 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
                 workflowId: 'email-changed',
                 subscriberId: session.user.id,
                 payload: {
-                  oldEmail: previousEmail,
+                  oldEmail: oldEmail,
                   newEmail: currentEmail,
                   timestamp: new Date().toISOString(),
                 },
@@ -165,7 +166,7 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
       
       // Update tracked email
       if (currentEmail) {
-        setPreviousEmail(currentEmail);
+        previousEmailRef.current = currentEmail;
       }
       
       if (session?.user) {