docs: add AGENTS.md, skills, and Cursor rules entry for agents

[cs-raj]

Summary

Adds repository-local guidance for contributors and AI agents: a root AGENTS.md entry point and focused skills/*/SKILL.md files (YAML frontmatter with name and description, as agreed). Optional .cursor/rules/README.md sends Cursor users to AGENTS.md only, without duplicating prose or requiring .mdc rules.

What’s included

• AGENTS.md — Project purpose, stack summary, commands, links to existing GitHub workflows (security/policy scans; not build/lint CI), and a table of skills.
• skills/README.md — Short “when to use which skill” index.
• skills/dev-workflow — Install, .env, npm scripts, codegen prerequisites, CI overview.
• skills/contentstack-kickstart — Delivery SDK, GraphQL, codegen, gql/, env, Live Preview wiring.
• skills/framework — Next.js 16 App Router layout, server vs client components, Tailwind, @/*.
• skills/testing — Lint and build as quality gates; documents that there is no automated test suite in-repo.
• skills/code-review — PR checklist (secrets, generated code, preview paths).
• .cursor/rules/README.md — Pointer to AGENTS.md only.

[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.