Fire codebuff.referrer_attributed analytics from root layout

Adds a ReferrerTracker to the codebuff root layout so any signed-in user who
passed through /referrals/<code> gets attributed via PostHog (with \$set_once)
on whatever page they eventually land on. Split the localStorage key so the
tracker and the /onboard welcome card don't race to clear each other.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: jahooma

common/src/constants/analytics-events.ts

@@ -62,6 +62,9 @@ export enum AnalyticsEvent {
   ONBOARD_PAGE_RUN_COMMAND_COPIED = 'onboard_page.run_command_copied',
   ONBOARD_PAGE_INSTALL_COMMAND_COPIED = 'onboard_page.install_command_copied',
 
+  // Web - Creator Attribution
+  CODEBUFF_REFERRER_ATTRIBUTED = 'codebuff.referrer_attributed',
+
   // Web - Install Dialog
   INSTALL_DIALOG_CD_COMMAND_COPIED = 'install_dialog.cd_command_copied',
   INSTALL_DIALOG_RUN_COMMAND_COPIED = 'install_dialog.run_command_copied',

web/src/app/layout.tsx

@@ -7,6 +7,7 @@ import { Footer } from '@/components/footer'
 import { LayoutWrapper } from '@/components/layout-wrapper'
 import { Navbar } from '@/components/navbar/navbar'
 import QueryProvider from '@/components/providers/query-client-provider'
+import { ReferrerTracker } from '@/components/referral/referrer-tracker'
 import { ThemeProvider } from '@/components/theme-provider'
 import { Toaster } from '@/components/ui/toaster'
 import { siteConfig } from '@/lib/constant'
@@ -66,6 +67,7 @@ export default function RootLayout({
           <SessionProvider>
             <QueryProvider>
               <PostHogProvider>
+                <ReferrerTracker />
                 <Navbar />
                 <div className="flex-grow">
                   <LayoutWrapper>{children}</LayoutWrapper>

web/src/components/onboard/welcome-card.tsx

@@ -16,10 +16,10 @@ export function WelcomeCard({
   const [referrer, setReferrer] = useState<string | null>(null)
 
   useEffect(() => {
-    const stored = localStorage.getItem('codebuff_referrer')
+    const stored = localStorage.getItem('codebuff_referrer_display')
     if (stored) {
       setReferrer(stored)
-      localStorage.removeItem('codebuff_referrer')
+      localStorage.removeItem('codebuff_referrer_display')
     }
   }, [])
 

web/src/components/referral/persist-referrer.tsx

@@ -6,6 +6,7 @@ export function PersistReferrer({ referrer }: { referrer: string }) {
   useEffect(() => {
     if (referrer) {
       localStorage.setItem('codebuff_referrer', referrer)
+      localStorage.setItem('codebuff_referrer_display', referrer)
     }
   }, [referrer])
 

web/src/components/referral/referrer-tracker.tsx

@@ -0,0 +1,20 @@
+'use client'
+
+import { AnalyticsEvent } from '@codebuff/common/constants/analytics-events'
+import posthog from 'posthog-js'
+import { useEffect } from 'react'
+
+export function ReferrerTracker() {
+  useEffect(() => {
+    const referrer = localStorage.getItem('codebuff_referrer')
+    if (referrer) {
+      posthog.capture(AnalyticsEvent.CODEBUFF_REFERRER_ATTRIBUTED, {
+        referrer,
+        $set_once: { codebuff_referrer: referrer },
+      })
+      localStorage.removeItem('codebuff_referrer')
+    }
+  }, [])
+
+  return null
+}