feat: visualize AIGuard evidence in Studio

[hyeokjun32]

Summary

• Added a Local Studio AIGuard Evidence panel for diagnosis reports.
• Replayed demo guard evidence with guard_verdict, primary reason, source, evidence items, suspected causes, and recommendations.
• Connected Studio demo evidence to Lab-owned deployment decisions while keeping AIGuard optional.

Validation

• node --check inferedgelab/studio/static/app.js
• PYTHONDONTWRITEBYTECODE=1 poetry run python3 -m pytest tests/test_studio_routes.py -q
• PYTHONDONTWRITEBYTECODE=1 poetry run python3 -m pytest -q

Impact

• Lets users inspect why a result requires review directly in the local browser workflow.
• Completes Phase 5 Studio visualization for AIGuard evidence without adding SaaS infrastructure.

Notes

• AIGuard remains an optional deterministic evidence provider.
• Lab remains the final deployment decision owner.
• No DB/queue/auth/billing behavior added.