Add comprehensive guides for various Epic Stack skills

[rubenpenap]

Summary

This PR adds 11 comprehensive skill guides (SKILL.md files) to .cursor/skills/ that document Epic Stack best practices and patterns. Each guide includes when to use it, patterns, conventions, common mistakes, and references.

Guides added:

• epic-auth: Authentication, sessions, OAuth, 2FA, and passkeys
• epic-caching: Caching with cachified, SQLite cache, and LRU cache
• epic-database: Prisma, SQLite, and LiteFS
• epic-deployment: Deployment with Fly.io, multi-region setup, and CI/CD
• epic-forms: Forms with Conform and validation with Zod
• epic-permissions: RBAC system and permissions
• epic-react-best-practices: React patterns, performance optimization, and code quality
• epic-routing: Routing with React Router and react-router-auto-routes
• epic-security: Security practices including CSP, rate limiting, and session security
• epic-testing: Testing with Vitest and Playwright
• epic-ui-guidelines: UI/UX guidelines, accessibility, and component usage

These guides serve as comprehensive references to help developers understand and implement Epic Stack best practices and conventions.

Test Plan

No tests required because:

• Only documentation files are added (.cursor/skills/*/SKILL.md)
• No functional code changes
• No changes to business logic
• Does not affect application execution

Suggested verification steps:

1. Verify all 11 SKILL.md files exist in .cursor/skills/
2. Check markdown formatting is correct
3. Review that references to codebase files are accurate
4. Confirm Cursor can properly read these skills

Checklist

• Tests updated (N/A - documentation only)
• Docs updated (The added files are the new documentation)

Screenshots

N/A - Only documentation files were added.

[cr101]

Thank you for putting this together.

Do you think it would be better to place the skill folders inside a .github/skills/ directory at the root of the repository instead to ensure that AI agents (Cursor , Claude Code, VS Code Copilot, and other emerging agentic frameworks) can find and use the custom instructions?

[rubenpenap]

Hey Cris! Thanks for the suggestion, that makes a lot of sense

I initially placed the skills under .cursor mainly because the folder already existed and felt like a natural starting point. That said, I totally agree that .github/skills/ at the repo root is probably a better, more discoverable convention for agents across Cursor, Claude Code, Copilot, and others.

Happy to move them there if you think that’s the right call, no problem at all on my side. Let me know what you prefer and I’ll adjust it.