chore: simplify standalone Compose setup

.env.example

@@ -1,8 +1,16 @@
-# Exact public origin; use HTTPS behind your reverse proxy in production.
+# Public origin. Set your HTTPS origin when using a reverse proxy.
 SITE_URL=http://localhost:3000
-# Native development/maintenance database and uploads directory.
+PORT=3000
+# Set 0.0.0.0 to expose the port beyond this machine.
+BIND_ADDRESS=127.0.0.1
+# Native development only; Docker always stores data at /data.
 DATA_DIR=./data
-# Optional. If absent, initialization generates a secret in DATA_DIR/auth-secret.
+# These defaults preserve volumes from the previous production deployment.
+PORTFOLIO_DATA_VOLUME=portfolio_portfolio-data
+PORTFOLIO_CACHE_VOLUME=portfolio_next-image-cache
+# Optional; otherwise generated once and kept in the data volume.
 # BETTER_AUTH_SECRET=replace-with-at-least-32-random-characters
-# For compose.selfhost.yaml, directory mounted at /data:
-PORTFOLIO_DATA_DIR=./data
+# Override if your server needs a registry mirror.
+NPM_REGISTRY=https://registry.npmjs.org/
+# Optional existing Caddy network (Linux server path separator):
+# COMPOSE_FILE=compose.yaml:compose.caddy.yaml