Make documentation standalone and generalize examples

.env.example

@@ -1,6 +1,5 @@
-# Template for the app stack's .env. The workspace root's scripts/setup.sh copies
-# this file to .env on first run and then keeps the shared keys in sync with the
-# root .env. Secrets stay as `changethis` here and are generated locally.
+# Template for the app stack. `make init` copies this to .env and generates
+# initial secrets. Keep real credentials in .env, which is ignored by git.
 
 # Domain Traefik routes on and acquires TLS certificates for.
 DOMAIN=localhost
@@ -19,7 +18,7 @@ STACK_NAME=fluksio-app
 # only matter to a dashboard served from elsewhere, such as the Vite server.
 BACKEND_CORS_ORIGINS="http://localhost,http://localhost:5173,http://app.localhost,https://localhost,https://localhost:5173"
 SECRET_KEY=changethis
-FIRST_SUPERUSER=admin@fluksio.com
+FIRST_SUPERUSER=admin@example.com
 FIRST_SUPERUSER_PASSWORD=changethis
 
 # Emails
@@ -65,7 +64,7 @@ MCP_ENABLED=true
 # under Admin.
 SIGNUP_ENABLED=false
 
-# Local time for schedules; set from the root .env by scripts/setup.sh.
+# Timezone for schedules. Set this to the timezone your flows should use.
 TZ=UTC
 
 # A camera's live view between networks: STUN and TURN servers, comma