Implement operational red-teaming starter artifacts, README sections, templates, and CI workflow

[requie]

Motivation

• Turn prior recommendation-only guidance into practical, first-wave artifacts teams can adopt immediately.
• Provide repeatable artifacts (workshop template, PR checklist, evaluation harness guidance) to reduce onboarding friction and standardize exercises.
• Offer a CI starter workflow so teams can begin automated regression and reporting for red-team runs.

Description

• Added new operational sections to README.md and updated the table of contents to include: Implementation Quickstart (30/60/90), Evaluation Harness (Reference Implementation), Agentic AI Attack Trees + Controls Mapping, AI Harm Severity and Triage Model, and Secure SDLC Integration Artifacts.
• Introduced reusable templates at templates/threat-modeling-workshop.md and templates/ai-security-pr-checklist.md to support structured workshops and PR-level AI security checks.
• Added a baseline GitHub Actions workflow at .github/workflows/ai-redteam-regression.yml that installs dependencies, runs an example baseline scan, and uploads reports as artifacts.
• Included a minimal evaluation-harness layout and scoring guidance in the README (example folder structure and suggested metrics/release gates).

Testing

• Verified the new README sections are present and linked via a targeted search with rg for the new section headings; the search succeeded.
• Inspected the README and new content slices using nl -ba README.md | sed -n to confirm insertion points and content; inspection succeeded.
• Confirmed the two templates exist and their contents with nl -ba templates/threat-modeling-workshop.md and nl -ba templates/ai-security-pr-checklist.md; both file checks succeeded.
• Verified the workflow file exists and its content with nl -ba .github/workflows/ai-redteam-regression.yml and confirmed repository working-tree status with git status --short; both checks succeeded.

[chatgpt-codex-connector]

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