#10167 fix(core): Ensure project `.env` files are created with 0600 permissions Pull request opened by edgarrmondragon Description SSIA Checklist • I have read the contribution guide Was generative AI tooling used to co-author this PR? • Yes (please specify the tool below) Generated-by: Claude Code following the agentic coding guidelines Related Issues • Closes #XXXX Summary by Sourcery Ensure project

.env

files are created with secure, owner-only permissions when settings are written. Bug Fixes: • Prevent newly created

.env

files from defaulting to world-readable permissions by explicitly setting owner-only mode. Tests: • Add a platform-aware test verifying

.env

files are created with 0600 permissions, skipping enforcement on Windows. Summary by Sourcery Ensure

.env

files created by the settings store are restricted to owner-only permissions to protect secrets. Bug Fixes: • Prevent newly created

.env

files from being world-readable by setting their file mode to owner read/write only. Tests: • Add a non-Windows test verifying that created

.env

files have owner-only (0o600) permissions. meltano/meltano