fix: Use 'normal' mode instead of 'sequential' for playlist playback

The 'sequential' mode in Liquidsoap starts playback at a random position
in the playlist, causing tracks to play out of order. Switching to 'normal'
mode ensures the playlist starts from the beginning and plays sequentially
through all tracks in order.

docker/asteroid-radio-docker.liq

@@ -23,7 +23,7 @@ settings.server.telnet.bind_addr.set("0.0.0.0")
 # This file is managed by Asteroid's stream control system
 # Falls back to directory scan if playlist file doesn't exist
 radio = playlist(
-  mode="sequential",  # Play through playlist in order, then loop
+  mode="normal",      # Normal mode: play sequentially without initial randomization
   reload=300,         # Check for playlist updates every 5 minutes
   reload_mode="watch",  # Watch file for changes (more efficient than polling)
   "/app/stream-queue.m3u"