feat: add Core 4 contract conformance check

[hyeokjun32]

Summary

• Added a local-first Core 4 conformance smoke command for Forge manifest/metadata, Runtime result, Lab compare/deployment decision, and AIGuard guard_analysis evidence.
• Added lightweight Forge conformance fixtures aligned with the bundled Runtime demo evidence.
• Documented the new command in README.

Validation

• poetry run python3 -m pytest -q
• poetry run inferedgelab portfolio-demo-check
• poetry run inferedgelab core4-conformance-check

Impact

• Provides a pre-submission guardrail for the cross-repo InferEdge contract chain.
• Keeps existing metadata/result/compare/guard schemas unchanged.
• Reinforces Lab as the deployment decision owner while AIGuard remains optional deterministic diagnosis evidence.

Notes

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