added batchcleanupservice

[gentledepp]

fixes #1349

Summary: Batch Cleanup Service Implementation

What We Implemented

New Batch Cleanup Service - A comprehensive solution to automatically manage and clean up expired batch directories that can accumulate from failed sync sessions and network interruptions.

Key Components Added

1. Core Service Infrastructure

• IBatchCleanupService - Interface defining cleanup operations
• BatchCleanupService - Default implementation with robust error handling
• 486 comprehensive unit tests covering all scenarios and edge cases

2. Directory Naming Standardization

• Changed BatchInfo directory format from yyyy_MM_dd_ss to yyyyMMddHHmm
• Added explanatory comments in code explaining the importance of this format for cleanup service

3. SyncOptions Configuration

• BatchRetentionPeriod - Configurable retention period (default: 1 hour)
• BatchCleanupWhenSessionEnds - Option for immediate vs deferred cleanup (default: false)

4. Automatic Integration

• LocalOrchestrator & RemoteOrchestrator - Auto-cleanup on session start
• WebServerAgent - Dependency injection support for web scenarios
• DependencyInjection - Service registration for ASP.NET Core applications

How It Improves Batch Cleanup

Prevents Disk Space Issues

• Automatically removes orphaned batch directories from failed sync sessions
• Configurable retention periods prevent indefinite accumulation
• Robust timestamp-based identification of expired batches

Production-Ready Reliability

• Graceful error handling - Individual directory cleanup failures don't break the entire operation
• Cancellation support - Respects CancellationToken for clean shutdowns
• Input validation - Throws meaningful ArgumentExceptions for invalid parameters
• Non-blocking - Continues cleanup even if some directories are locked or inaccessible

Flexible Configuration

• Multiple overloads - Works with SyncOptions or direct parameters
• Override support - Can override configured retention period per operation
• Inspection capabilities - GetExpiredBatchDirectoriesAsync for audit/monitoring without cleanup
• Zero retention period - Disables time-based cleanup when set to TimeSpan.Zero

Smart Directory Recognition

• Format validation - Only processes directories matching yyyyMMddHHmm* pattern
• Boundary handling - Correctly handles edge cases at cutoff timestamps (≤ comparison)
• Ordering - Returns expired directories in chronological order for predictable cleanup

Seamless Integration

• Automatic activation - No code changes needed, runs automatically on sync session start
• DI-friendly - Full dependency injection support for web applications
• Backward compatible - Doesn't affect existing sync functionality

This implementation provides a complete, production-ready solution for managing batch directory lifecycle, preventing disk space issues while maintaining sync performance and reliability.