[IMPROVEMENT] Implement agent object pooling for bulk operations

[kyegomez]

[IMPROVEMENT] Implement agent object pooling for bulk operations

Description
Create an object pool system for agent instances to reduce allocation overhead during bulk initialization and improve memory efficiency for repeated agent creation/destruction patterns.

Background
Applications that frequently create and destroy agents (like batch processing, testing, or simulation scenarios) suffer from repeated allocation/deallocation overhead. Object pooling can significantly improve performance for these use cases.

Proposed Solution

pub struct AgentPool<M> {
    available: VecDeque<Agent<M>>,
    max_size: usize,
    factory: Box<dyn Fn() -> Agent<M>>,
}

impl<M> AgentPool<M> {
    pub fn acquire(&mut self) -> PooledAgent<M> {
        // Return reusable agent instance
    }
    
    pub fn return_agent(&mut self, agent: Agent<M>) {
        // Reset and return to pool
    }
}

Key Features

• Configurable pool size limits
• Automatic agent reset/cleanup on return
• Thread-safe pool implementation option
• Integration with existing agent builder pattern
• Performance metrics and monitoring

Benefits

• Reduced allocation overhead for repeated operations
• Lower garbage collection pressure
• Improved memory locality
• Better performance for batch processing scenarios

Use Cases

• Batch processing workflows
• Testing scenarios with many agent instances
• Simulation environments
• Performance benchmarking

Acceptance Criteria

• Implement thread-safe agent pool with configurable sizing
• Add automatic agent state reset functionality
• Achieve 40%+ performance improvement for repeated create/destroy operations
• Integrate with existing agent creation patterns
• Add comprehensive benchmarks and documentation
• Implement pool monitoring and metrics collection