chore: add env_file: stack.env to all compose services

Portainer git-stack deployments require an explicit env_file reference
in the compose file to load variables from the repo's stack.env.
Adds env_file: [stack.env] before every service-level environment:
block across all 10 stacks.

stacks/authentik/docker-compose.yml

@@ -12,6 +12,8 @@ services:
     restart: unless-stopped
     command: server
     networks: [authentik, edge]
+    env_file:
+      - stack.env
     environment:
       AUTHENTIK_REDIS__HOST: authentik-redis
       AUTHENTIK_POSTGRESQL__HOST: authentik-db
@@ -34,6 +36,8 @@ services:
     restart: unless-stopped
     command: worker
     networks: [authentik]
+    env_file:
+      - stack.env
     environment:
       AUTHENTIK_REDIS__HOST: authentik-redis
       AUTHENTIK_POSTGRESQL__HOST: authentik-db
@@ -53,6 +57,8 @@ services:
     image: postgres:16-alpine
     restart: unless-stopped
     networks: [authentik]
+    env_file:
+      - stack.env
     environment:
       POSTGRES_USER: ${AUTHENTIK_DB_USER:-authentik}
       POSTGRES_PASSWORD: ${AUTHENTIK_DB_PASSWORD}