Create logged-out view for group chat invites (#10598)

Co-authored-by: Samuel Newman <mozzius@protonmail.com>

src/components/hooks/useLandingEntry.ts

@@ -0,0 +1,31 @@
+import {useEffect, useState} from 'react'
+
+import {httpStarterPackUriToAtUri} from '#/lib/strings/starter-pack'
+import {useSetActiveStarterPack} from '#/state/shell/landing'
+
+export function useLandingEntry() {
+  const [ready, setReady] = useState(false)
+  const setActiveStarterPack = useSetActiveStarterPack()
+
+  useEffect(() => {
+    const href = window.location.href
+    const url = new URL(href)
+
+    // Check for starter pack
+    const atUri = httpStarterPackUriToAtUri(href)
+    if (atUri) {
+      // Determines if an App Clip is loading this landing page
+      const isClip = url.searchParams.get('clip') === 'true'
+      setActiveStarterPack({
+        uri: atUri,
+        isClip,
+      })
+      setReady(true)
+      return
+    }
+
+    setReady(true)
+  }, [setActiveStarterPack])
+
+  return ready
+}