docs: add AGENTS.md, Cursor rules, and agent skills (DX-5367)

[harshitha-cstk]

Summary

• Add AGENTS.md as the repository entry point for agents and contributors (package scope vs CDA/CMA SDKs, tech stack, layout, npm commands, test/build notes).
• Add .cursor/rules/ (README plus dev-workflow, TypeScript, Contentstack utils domain, testing, and always-applied code-review rules).
• Add skills/ with focused SKILL docs for code review, testing, and the utils mental model.
• Extend .talismanrc so pre-commit Talisman scans ignore false positives on the new markdown guidance files.

Notes

No runtime or API changes. Hooks (Snyk/Talisman) pass with the updated Talisman allowlist.

[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	0	500	✅ Passed
🔵 Low Severity	0	0	1000	✅ Passed

⏱️ SLA Breach Summary

✅ No SLA breaches detected. All vulnerabilities are within acceptable time thresholds.

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	0	90 / 365 days	✅ Passed
🔵 Low	0	0	180 / 365 days	✅ Passed

✅ BUILD PASSED - All security checks passed

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟢	Statements	99.12%	672/678
🟢	Branches	91.96%	503/547
🟢	Functions	100%	144/144
🟢	Lines	99.36%	621/625

Test suite run success

415 tests passing in 21 suites.

Report generated by 🧪jest coverage report action from 30afae3

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟢	Statements	99.12%	672/678
🟢	Branches	91.96%	503/547
🟢	Functions	100%	144/144
🟢	Lines	99.36%	621/625

Test suite run success

415 tests passing in 21 suites.

Report generated by 🧪jest coverage report action from 30afae3