Bug: Tests fail when Docker is unavailable

Description

Running pytest on environments where Docker is not installed or not running currently raises a DockerException during fixture setup, causing the entire test suite to fail.

Docker-backed fixtures defined in conftest.py should first detect whether Docker is available and skip the dependent tests gracefully if it is not.

Expected Behavior

• Docker availability should be checked before initializing Docker containers.
• Tests that depend on Docker should be skipped when Docker is unavailable.
• The test report should show these tests as skipped, not failed.

Actual Behavior

• pytest raises a DockerException during PostgresContainer fixture setup.
• This causes session-level errors, which fail the entire test run instead of skipping Docker-dependent tests.

Affected Files

• conftest.py (fixtures using PostgresContainer)
• conftest.py (Docker-backed test fixtures)

Suggested Fix

• Add a Docker availability check before starting containers.
• Use pytest.skip() or conditional fixtures to skip tests when Docker is not accessible.