initial commit

app/composables/useWebRTCFailureReason.js

@@ -0,0 +1,18 @@
+/**
+ * Fetch WebRTC failure reason (e.g. wrong host). Pure: same inputs → same output.
+ * @returns {Promise<{ wrongHost: { serverHostname: string, clientHostname: string } | null }>} Failure reason or null.
+ */
+export async function getWebRTCFailureReason() {
+  try {
+    const res = await $fetch('/api/live/debug-request-host', { credentials: 'include' })
+    const clientHostname = typeof window !== 'undefined' ? window.location.hostname : ''
+    const serverHostname = res?.hostname ?? ''
+    if (serverHostname && clientHostname && serverHostname !== clientHostname) {
+      return { wrongHost: { serverHostname, clientHostname } }
+    }
+  }
+  catch {
+    // ignore
+  }
+  return { wrongHost: null }
+}