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/hooks/memory-persistence/session-end.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+# Stop Hook (Session End) - Persist learnings when session ends
+#
+# Runs when Claude session ends. Creates/updates session log file
+# with timestamp for continuity tracking.
+#
+# Configured in .cursor/hooks.json:
+#   sessionEnd -> node .cursor/scripts/hooks/session-end.js
+# This shell version is a fallback for environments without Node.
+
+ROOT="$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
+SESSIONS_DIR="${ROOT}/.cursor/sessions"
+TODAY=$(date '+%Y-%m-%d')
+SESSION_FILE="${SESSIONS_DIR}/${TODAY}-session.tmp"
+
+mkdir -p "$SESSIONS_DIR"
+
+# If session file exists for today, update the end time
+if [ -f "$SESSION_FILE" ]; then
+  # Update Last Updated timestamp
+  sed -i '' "s/\*\*Last Updated:\*\*.*/\*\*Last Updated:\*\* $(date '+%H:%M')/" "$SESSION_FILE" 2>/dev/null || \
+  sed -i "s/\*\*Last Updated:\*\*.*/\*\*Last Updated:\*\* $(date '+%H:%M')/" "$SESSION_FILE" 2>/dev/null
+  echo "[SessionEnd] Updated session file: $SESSION_FILE" >&2
+else
+  # Create new session file with template
+  cat > "$SESSION_FILE" << EOF
+# Session: $(date '+%Y-%m-%d')
+**Date:** $TODAY
+**Started:** $(date '+%H:%M')
+**Last Updated:** $(date '+%H:%M')
+
+---
+
+## Current State
+
+[Session context goes here]
+
+### Completed
+- [ ]
+
+### In Progress
+- [ ]
+
+### Notes for Next Session
+-
+
+### Context to Load
+\`\`\`
+[relevant files]
+\`\`\`
+EOF
+  echo "[SessionEnd] Created session file: $SESSION_FILE" >&2
+fi