feat: Add ICECAST_HOSTNAME config for YP directory registration

- Add hostname substitution in icecast-entrypoint.sh
- Update environment.sh.template with ICECAST_HOSTNAME option
- Defaults to localhost for dev, production sets ice.asteroid.radio
- Fixes YP directories showing localhost:8000 as stream URL

docker/environment.sh.template

@@ -16,3 +16,8 @@ export ASTEROID_DB_PASSWORD=asteroid_db_2025
 # Set to 'true' ONLY on production (asteroid.radio)
 # Leave unset or 'false' for development to avoid polluting public listings
 # export ICECAST_ENABLE_YP=true
+
+# Icecast Hostname (reported to YP directories)
+# Production should set this to the public hostname
+# Dev defaults to 'localhost' if unset
+# export ICECAST_HOSTNAME=ice.asteroid.radio

docker/icecast-entrypoint.sh

@@ -1,10 +1,16 @@
 #!/bin/sh
 
 # Generate icecast.xml from base config
-# If ICECAST_ENABLE_YP=true, insert YP directory blocks
+# - Substitute hostname (defaults to localhost for dev)
+# - If ICECAST_ENABLE_YP=true, insert YP directory blocks
 
 cp /etc/icecast.xml.base /etc/icecast.xml
 
+# Set hostname (defaults to localhost if not specified)
+ICECAST_HOSTNAME=${ICECAST_HOSTNAME:-localhost}
+echo "Icecast hostname: $ICECAST_HOSTNAME"
+sed -i "s|<hostname>localhost</hostname>|<hostname>$ICECAST_HOSTNAME</hostname>|" /etc/icecast.xml
+
 if [ "$ICECAST_ENABLE_YP" = "true" ]; then
     echo "YP directory publishing ENABLED"
     # Insert YP config before closing </icecast> tag