docs: add AGENTS.md, skills/, and Cursor rules for contributors

[cs-raj]

Summary

This PR adds contributor and AI-agent documentation aligned with the Contentstack “AGENTS + skills” pattern: one root guide, per-topic SKILL.md files, and a minimal Cursor rules pointer so editor config does not duplicate prose.

Changes

• AGENTS.md — Project purpose, tech stack, npm commands, GitHub workflow links (policy/SCA), and a table of all skills with one-line summaries.
• skills/README.md — Short pointer to AGENTS.md and plain links to each SKILL.md (no duplicate “when to use” table).
• skills/*/SKILL.md — Six topics with YAML frontmatter (name, description):
  • dev-workflow — local setup, scripts, what CI does and does not run.
  • contentstack-kickstart — getStack isolation, Live Preview flow, env vars, entry files.
  • typescript-style — strict TS, @/* paths, client boundary, ESLint.
  • testing — no automated runner today; lint/build and manual checks.
  • code-review — PR checklist for this small codebase.
  • framework — App Router, next.config.mjs, Tailwind v4, PostCSS.
• .cursor/rules/README.md — Directs Cursor users to AGENTS.md and skills/*/SKILL.md.

[github-actions]

🔒 Security Scan Results

ℹ️ Note: Only vulnerabilities with available fixes (upgrades or patches) are counted toward thresholds.

Check Type	Count (with fixes)	Without fixes	Threshold	Result
🔴 Critical Severity	0	0	10	✅ Passed
🟠 High Severity	0	0	25	✅ Passed
🟡 Medium Severity	0	20	500	✅ Passed
🔵 Low Severity	0	0	1000	✅ Passed

⏱️ SLA Breach Summary

⚠️ Warning: The following vulnerabilities have exceeded their SLA thresholds (days since publication).

Severity	Breaches (with fixes)	Breaches (no fixes)	SLA Threshold (with/no fixes)	Status
🔴 Critical	0	0	15 / 30 days	✅ Passed
🟠 High	0	0	30 / 120 days	✅ Passed
🟡 Medium	0	18	90 / 365 days	⚠️ Warning
🔵 Low	0	0	180 / 365 days	✅ Passed

ℹ️ Vulnerabilities Without Available Fixes (Informational Only)

The following vulnerabilities were detected but do not have fixes available (no upgrade or patch). These are excluded from failure thresholds:

• Critical without fixes: 0
• High without fixes: 0
• Medium without fixes: 20
• Low without fixes: 0

⚠️ BUILD PASSED WITH WARNINGS - SLA breaches detected for issues without available fixes

Consider reviewing these vulnerabilities when fixes become available.