Docker: read every setting from a .env file

Each folder gets a .env.example listing every homeserver, admin panel
and web client setting with its default (empty means the default).
Compose reads .env for ports, registry and the PostgreSQL password, and
passes it to the containers through env_file; the compose files keep
only the database driver, connection string and internal addresses.
.env is git-ignored.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Docker-AIO/docker-compose.postgresql.yml

@@ -2,7 +2,8 @@
 # client and PostgreSQL in one container, built from this checkout.
 #
 #   cd Docker-AIO
-#   WARP_SERVER_NAME=matrix.example.org docker compose -f docker-compose.postgresql.yml up -d --build
+#   cp .env.example .env      # then edit it
+#   docker compose -f docker-compose.postgresql.yml up -d --build
 #
 # PostgreSQL runs inside the container, listening only on a Unix socket
 # there, with its data in /data/postgres in the warp-data volume.
@@ -25,14 +26,11 @@ services:
     restart: unless-stopped
     # PostgreSQL's fast shutdown runs after the homeserver's; give both time.
     stop_grace_period: 30s
+    env_file: .env
     environment:
-      WARP_SERVER_NAME: ${WARP_SERVER_NAME:-localhost}
-      WARP_WELL_KNOWN_CLIENT_BASE_URL: ${WARP_PUBLIC_BASEURL:-http://localhost:8008}
       WARP_AIO_EMBEDDED_POSTGRES: "true"
       WARP_DB_DRIVER: postgres
       WARP_DB_CONNECTION_STRING: postgres:///warp?host=/run/postgresql&user=warp&sslmode=disable
-      WARP_REGISTRATION_ENABLED: ${WARP_REGISTRATION_ENABLED:-false}
-      WARP_FEDERATION_ENABLED: ${WARP_FEDERATION_ENABLED:-false}
     volumes:
       - warp-data:/data
     ports: