Add test for markdown report emoji encoding

[aviralgarg05]

Summary

Add test for SuiteResult.to_markdown() to verify emoji characters render correctly.

Tasks

• Add a test in tests/test_reporting.py (or create if needed).
• Create a SuiteResult with passing and failing runs.
• Assert the markdown output contains ✅ and ❌ characters.
• Verify UTF-8 encoding is preserved.

Acceptance criteria

• Test passes on all platforms (including Windows).
• poetry run pytest passes.