Merge origin/main; resolve Docker file conflicts

PR #1 was squash-merged to main with the initial Dockerfile/README.
Keep the Compose-enhanced versions from this branch (superset).

.env.example

@@ -2,6 +2,7 @@ AUTH_SECRET=change-me-to-a-long-random-string
 # Optional: path to SQLite file (default ./data/rfid.db)
 # RFID_DB_PATH=./data/rfid.db
 
+<<<<<<< HEAD
 # Docker Compose published port (default 3000)
 # RFID_PORT=3000
 
@@ -10,6 +11,8 @@ AUTH_SECRET=change-me-to-a-long-random-string
 # CREATE_USER_PASSWORD=changeme
 # CREATE_USER_NAME=Admin
 
+=======
+>>>>>>> origin/main
 # Optional OIDC (Authentik, Keycloak, Authelia, etc.)
 # AUTH_OIDC_ISSUER=https://sso.example.com/application/o/rfid/
 # AUTH_OIDC_CLIENT_ID=