feat(analytics): add behavior and payment funnel tracking

src/app/_components/back-button.tsx

@@ -6,6 +6,7 @@ import Link, { type LinkProps } from "next/link";
 interface BackButtonBaseProps {
   className?: string;
   ariaLabel?: string;
+  analyticsKey?: string;
   iconSize?: number;
   variant?: "floating" | "soft" | "ghost" | "dark";
 }
@@ -41,6 +42,7 @@ export function BackButton({
   onClick,
   className,
   ariaLabel = "Back",
+  analyticsKey,
   iconSize = 24,
   variant = "floating",
 }: BackButtonProps) {
@@ -57,7 +59,13 @@ export function BackButton({
 
   if (href) {
     return (
-      <Link href={href} className={buttonClassName} aria-label={ariaLabel}>
+      <Link
+        href={href}
+        className={buttonClassName}
+        aria-label={ariaLabel}
+        data-analytics-key={analyticsKey}
+        data-analytics-label={ariaLabel}
+      >
         {icon}
       </Link>
     );
@@ -69,6 +77,8 @@ export function BackButton({
       className={buttonClassName}
       onClick={onClick}
       aria-label={ariaLabel}
+      data-analytics-key={analyticsKey}
+      data-analytics-label={ariaLabel}
     >
       {icon}
     </button>