Podcast tab: show podcast.necloud.us inside the app

Audio and Podcast now share kept-alive frames that stay loaded while hidden.
A plain-http address still falls back to a launcher (a secure page cannot
frame http content).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

.env.example

@@ -10,4 +10,4 @@ AUDIOBOOKS_URL=https://audiobooks.necloud.us
 # First-time passkey enrolment. If unset, a random code is printed in the server log while no passkey exists.
 HUB_SETUP_CODE=
 VERSE_URL=https://versebyversewithnate.us/admin
-PODCAST_URL=http://172.16.16.106:8383/
+PODCAST_URL=https://podcast.necloud.us/