Compose reads COMPOSE_PROFILES from .env automatically (no --profile flag
needed on every invocation), so adding it to .env.example lets developers
opt into the new "postgres" profile (or any other) once and forget about
it. Drive-by trims "Only starts this service if..." to "Only starts if..."
across compose.yaml, compose.nvidia.yaml, and the three setup/docker
compose files so all gated services use the same shorter phrasing.
Adds env-var interpolation for the bind host, host ports (HTTP/HTTPS,
MariaDB, PostgreSQL, LDAP), bridge-network name, and PHOTOPRISM_SITE_URL
so developers can spin up parallel dev environments via .env overrides.
Templates the traefik.docker.network labels on every Traefik-routed
service to follow the network rename, fixes the photoprism-vision and
dummy-ldap router/service name collisions, and documents the available
knobs in a new .env.example template (whitelisted in .gitignore).
Signed-off-by: Michael Mayer <michael@photoprism.app>
