feat: enhance login tracking and logout functionality

- Added session storage flag to track local login success, ensuring OAuth flows do not double track login events.
- Implemented tracking for logout events in both UserDropdown and AppSidebar components, resetting PostHog identity accordingly.
- Minor formatting adjustments in GoogleLoginButton and footer-new components for consistency.

surfsense_web/components/providers/PostHogIdentify.tsx

@@ -0,0 +1,49 @@
+"use client";
+
+import { useAtomValue } from "jotai";
+import { useEffect, useRef } from "react";
+import { currentUserAtom } from "@/atoms/user/user-query.atoms";
+import { identifyUser, resetUser } from "@/lib/posthog/events";
+
+/**
+ * Component that handles PostHog user identification.
+ * - Identifies users when they're logged in (user data is available)
+ * - Resets the PostHog identity when user logs out
+ *
+ * This should be rendered inside the PostHogProvider.
+ */
+export function PostHogIdentify() {
+	const { data: user, isSuccess, isError } = useAtomValue(currentUserAtom);
+	const previousUserIdRef = useRef<string | null>(null);
+
+	useEffect(() => {
+		// Only run on client side
+		if (typeof window === "undefined") return;
+
+		// User is logged in and we have their data
+		if (isSuccess && user?.id) {
+			const userId = String(user.id);
+
+			// Only identify if this is a new user or different from previous
+			if (previousUserIdRef.current !== userId) {
+				identifyUser(userId, {
+					email: user.email,
+					// Add any other user properties you want to track
+					is_superuser: user.is_superuser,
+					is_verified: user.is_verified,
+				});
+				previousUserIdRef.current = userId;
+			}
+		}
+
+		// User is not logged in (query failed due to auth error)
+		// and we previously had a user identified
+		if (isError && previousUserIdRef.current !== null) {
+			resetUser();
+			previousUserIdRef.current = null;
+		}
+	}, [user, isSuccess, isError]);
+
+	// This component doesn't render anything
+	return null;
+}