Add comprehensive comments to all source files and expand documentation

docker-compose.yml

@@ -1,3 +1,16 @@
+# docker-compose.yml
+# ==================
+#
+# Portainer stack definition.
+# Builds the image directly from the GitLab repository (main branch).
+#
+# Environment variables are set in Portainer under the stack's
+# Environment variables section. The container uses them directly,
+# so no .env file is required on disk.
+#
+# Named volumes keep the SQLite database and uploaded MP3s persistent
+# across container restarts and redeploys.
+
 services:
   booth:
     build:
@@ -12,10 +25,13 @@ services:
       - SMTP_USER=${SMTP_USER:-ai@hallsworth.ca}
       - SMTP_PASS=${SMTP_PASS}
       - SMTP_FROM=${SMTP_FROM:-ai@hallsworth.ca}
-      - ADMIN_ALERT_EMAIL=${ADMIN_ALERT_EMAIL:-}
       - PUBLIC_BASE_URL=${PUBLIC_BASE_URL}
       - BOOTH_NAME=${BOOTH_NAME:-Trollgorithm Theme Songs}
       - INTERNAL_PORT=${INTERNAL_PORT:-8000}
+      - PRICE_PER_VERSION=${PRICE_PER_VERSION:-10.00}
+      - CURRENCY=${CURRENCY:-CAD}
+      - DATABASE=${DATABASE:-/app/data/booth.db}
+      - UPLOAD_FOLDER=${UPLOAD_FOLDER:-/app/uploads}
     ports:
       - "${HOST_PORT:-127.0.0.1:8000}:${INTERNAL_PORT:-8000}"
     volumes: