fix: clarify local studio pipeline states

[hyeokjun32]

Summary

• Prioritized imported Runtime evidence over queued jobs in the Pipeline Flow state model.
• Marked AIGuard as optional when no guard evidence exists instead of showing it as idle.
• Added optional-state styling and static contract tests.
• Bumped Studio static asset references to v8.

Validation

• poetry run python3 -m pytest tests/test_studio_routes.py -q
• poetry run python3 -m pytest -q
• Manual HTTP check for /studio v8 assets and pipeline state helpers

Impact

• Prevents Runtime from staying stuck on running after Import succeeds.
• Makes AIGuard look intentionally optional rather than broken or unused.

Notes

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