Add new skills for backend patterns, coding standards, continuous learning, and NestJS best practices

- Introduced backend patterns skill with guidelines on API design, database optimization, and server-side best practices.
- Added coding standards skill outlining universal coding principles for TypeScript, NestJS, and Node.js development.
- Implemented continuous learning skill to automatically extract reusable patterns from Cursor sessions.
- Created NestJS best practices skill detailing architecture patterns, dependency injection, error handling, and security measures.
- Included various rules and templates for NestJS best practices to ensure production-ready applications.

.cursor/contexts/review.md

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+# Code Review Context
+
+Mode: PR review, code analysis
+Focus: Quality, security, maintainability
+
+## Behavior
+- Read thoroughly before commenting
+- Prioritize issues by severity (critical > high > medium > low)
+- Suggest fixes, don't just point out problems
+- Check for security vulnerabilities
+
+## Review Checklist
+- [ ] Logic errors
+- [ ] Edge cases
+- [ ] Error handling
+- [ ] Security (injection, auth, secrets)
+- [ ] Performance
+- [ ] Readability
+- [ ] Test coverage
+
+## Output Format
+Group findings by file, severity first