feat: add portfolio demo check

[hyeokjun32]

Summary

• Added a pre-submission portfolio demo check command for InferEdgeLab.
• Validates committed Local Studio demo fixtures, expected README/PPT metrics, portfolio docs, and Studio static assets.
• Keeps the workflow local-first without adding workers, queues, DB, auth, upload, or production SaaS behavior.

Validation

• poetry run inferedgelab portfolio-demo-check
• poetry run python3 -m pytest tests/test_demo_evidence_report.py -q
• poetry run python3 -m pytest -q

Impact

• Provides a single command to verify that portfolio demo evidence remains reproducible and aligned with README/PPT numbers.
• Strengthens InferEdgeLab as the submission entry point for the four-repo evidence pipeline.

Notes

• No result, compare, API, or deployment decision schema changed.
• Local Studio demo evidence remains in-memory and resets when the server restarts.