feat: Add comprehensive examples for advanced PraisonAI agent features

Added 7 new example files demonstrating advanced functionality:
- autoagents-hierarchical-generation.py: Hierarchical agent generation patterns
- advanced-graph-memory-integration.py: Graph-based memory systems
- advanced-callback-systems.py: Custom callback implementations
- production-guardrails-patterns.py: Production safety and guardrails
- advanced-state-management-patterns.py: Complex state handling
- advanced-memory-search-optimization.py: Memory search optimizations
- self-reflection-optimization-patterns.py: Self-improvement patterns

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

Author: github-actions[bot]