Make documentation standalone and generalize examples

docker/compose.yml

@@ -146,9 +146,8 @@ services:
       # rebuild would silently stop every phone being notified: the key they
       # subscribed against would be gone.
       - WEBPUSH_FILE=/data/webpush.json
-      # Schedules are written in local time: "off at 02:00" means the house's
-      # two in the morning, not the container's. Unset, an image is UTC, and a
-      # cron would be right twice a year.
+      # Cron schedules use this timezone. Set it to the timezone your flows
+      # should follow; the image defaults to UTC.
       - TZ=${TZ:-UTC}
 
     volumes:
@@ -248,7 +247,8 @@ services:
   # process per port. Credentials are minted by the backend from the same
   # TURN_SECRET (coturn's REST scheme), so nothing is stored here. The secret
   # goes in through a config file rather than the command line, which `ps`
-  # shows. See DEPLOY.md for ports, DNS and certificates.
+  # shows. Configure ports with TURN_MIN_PORT and TURN_MAX_PORT and mount
+  # certificates under TURN_CERT_DIR below.
   coturn:
     logging: *logging
     image: coturn/coturn:4.6.3
@@ -348,7 +348,6 @@ volumes:
   app-flow-data:
 
 networks:
-  # Shared with the website stack and whatever reverse proxy fronts them.
-  # Created once by the workspace root's scripts/setup.sh.
+  # External reverse-proxy network. Created by `make init`.
   proxy:
     external: true