fix(docker): wire CYCLONE_SFTP_PASSWORD via docker secret in compose override

Mirrors the existing admin_username / admin_pw pattern so the dev
compose loads SFTP creds from /tmp/cyclone-test-secrets/sftp_password
when present. Falls back to the CYCLONE_SFTP_PASSWORD env var if the
file is missing. Pre-existing env-var support from SP25+26 unchanged.

docker-compose.override.yml

@@ -15,6 +15,8 @@ secrets:
     file: /tmp/cyclone-test-secrets/admin_username
   cyclone_admin_password:
     file: /tmp/cyclone-test-secrets/admin_pw
+  cyclone_sftp_password:
+    file: /tmp/cyclone-test-secrets/sftp_password
 
 services:
   frontend: