fix: polish local studio demo presentation

[hyeokjun32]

Summary

• Prevented Recent jobs rows from overflowing when the browser zoom or width changes.
• Clarified Compare View speed labels so slower results are shown as slower instead of fractional faster.
• Documented the recommended portfolio demo flow around Load Demo Evidence.

Validation

• poetry run python3 -m pytest tests/test_studio_routes.py -q
• poetry run python3 -m pytest -q
• Manual browser check at /studio with Load Demo Evidence

Notes

• No DB, queue, upload, auth, billing, or production SaaS behavior was added.