docs(readme): document API and MCP modules

[SinatrasC]

Summary

Add kernelguard_api.py and kernelguard_mcp.py to the "Current Layout" section of the README so users discover the HTTP API and MCP server alongside the core detector module.

E2E pipeline test

This PR also exercises the end-to-end blue-submission auto-trigger pipeline:

KG red submission → Flywheel red attempt node → GitHub PR with KernelGuard-Red-Submission: <id> marker → blue-pr-sync workflow → workflow_run → trusted-blue-eval.

KernelGuard-Red-Submission: 8

Test plan

• README diff renders correctly (preview)
• blue-pr-sync recognizes the marker and reports is_blue_submission=true
• trusted-blue-eval auto-triggers via workflow_run (no manual dispatch)
• Blue evaluation result lands as a PR comment

[github-actions]

KernelGuard Blue Evaluation

• Evaluation job: 20
• Blue submission: 10
• Result: passed
• Target red submission caught: True
• Validation suite: TP 20/20, FP 20/20
• Surgicalness score: 1.0
• Workflow run: https://github.com/SinatrasC/kernelguard/actions/runs/25190580818

[SinatrasC]

Closing as superseded — this PR was a pipeline-validation run (README docs + an unrelated kernelguard.py docstring tweak), not a real detector fix. The trusted-blue-eval auto-trigger chain it was testing is now confirmed working through PRs #11–#15.