Implement executing tasks

stack.env.example

@@ -1,4 +1,9 @@
 APP_PORT=5006
+# Optional stack suffix for running a second isolated dev instance.
+# Example: GIA_STACK_ID=selfdev
+GIA_STACK_ID=
+# Optional deterministic port offset when STACK_ID is set.
+GIA_STACK_PORT_OFFSET=
 REPO_DIR=.
 APP_LOCAL_SETTINGS=./app/local_settings.py
 APP_DATABASE_FILE=./db.sqlite3
@@ -6,6 +11,9 @@ DOMAIN=example.com
 URL=https://example.com
 ALLOWED_HOSTS=example.com
 NOTIFY_TOPIC=example-topic
+# Optional explicit ntfy topic/url for scripts/quadlet/watchdog.sh
+NTFY_TOPIC=
+NTFY_URL_BASE=https://ntfy.sh
 CSRF_TRUSTED_ORIGINS=https://example.com
 DEBUG=y
 SECRET_KEY=
@@ -13,4 +21,4 @@ STATIC_ROOT=/code/static
 REGISTRATION_OPEN=0
 OPERATION=uwsgi
 BILLING_ENABLED=0
-COMPOSE_WS_ENABLED=true
+COMPOSE_WS_ENABLED=true