[MasyaSmv]

What changed

This branch expands the package beyond the v2.0.0 baseline with a streamed backup read path, object-based runtime inputs, a factory-driven container integration, stronger file-layer error handling, and updated package docs.

It also includes release-preparation metadata:

• add .codex to .gitignore
• add MIT license metadata to composer.json
• refresh CHANGELOG.md for 2.1.0
• align composer.lock with the current package manifest

Why

The package had accumulated shipped changes after v2.0.0, but the release metadata had not been updated. This PR brings the branch into a releasable state and documents the current public API direction.

Impact

• Adds FileStorageService::streamBackupData() for streamed backup reads.
• Introduces UserBackupCreateOptions and UserDataScope as preferred object-based inputs.
• Preserves legacy entry points while steering consumers toward the object-based API.
• Keeps saveBackupToFile() on the explicit-path contract introduced after v2.0.0.

Validation

• vendor/bin/phpunit
• composer validate --no-check-publish