Add optional episode titles to queued and live broadcasts

Store an episode_title on each broadcast, settable from the dashboard
or with set_show.php --title=, and show it under the show name on
index.php and under the heading on live.php.

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

assets/css/main.css

@@ -2656,6 +2656,10 @@ input, select, textarea {
 					margin-bottom: 0;
 				}
 
+				#header #one .show-heading .episode-title {
+					margin-bottom: 0.5em;
+				}
+
 /* Footer */
 
 	#footer .icons {