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/commands/update-codemaps.md

@@ -0,0 +1,17 @@
+# Update Codemaps
+
+Analyze the codebase structure and update architecture documentation:
+
+1. Scan all source files for imports, exports, and dependencies
+2. Generate token-lean codemaps in the following format:
+   - codemaps/architecture.md - Overall architecture
+   - codemaps/backend.md - Backend structure  
+   - codemaps/frontend.md - Frontend structure
+   - codemaps/data.md - Data models and schemas
+
+3. Calculate diff percentage from previous version
+4. If changes > 30%, request user approval before updating
+5. Add freshness timestamp to each codemap
+6. Save reports to .reports/codemap-diff.txt
+
+Use TypeScript/Node.js for analysis. Focus on high-level structure, not implementation details.