Add blog post: MongoDB Aggregation Pipeline Performance Optimization

Comprehensive tutorial covering advanced MongoDB aggregation pipeline optimization
techniques, including performance optimization, memory management, real-time analytics,
customer lifecycle analysis, text sentiment analysis, and SQL-familiar aggregation
patterns through QueryLeaf integration.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: rathboma