feat: Implement improved temp file management for CommandExecutor (fixes #142)

[plusplusoneplusplus]

Summary

This PR implements improved temporary file management for the CommandExecutor to address the race conditions, incomplete cleanup, and limited error recovery identified in issue #142.

Key Changes

🆕 New TempFileManager Class

• Enhanced cleanup coordination: Non-blocking queue-based cleanup system
• Retry mechanisms: Exponential backoff for failed cleanup operations
• Orphan detection: Automatic detection and cleanup of orphaned files from crashed processes
• Error recovery: Fallback temp directories and robust error handling
• Monitoring: Comprehensive metrics and logging for temp file operations

🔧 CommandExecutor Integration

• Replaced old temp file management with new TempFileManager
• Eliminated race conditions from monitor task cleanup skipping
• Improved process lifecycle management
• Enhanced error handling and recovery

⚙️ Configuration Settings

Added new environment variables for fine-tuning temp file management:

• TEMP_CLEANUP_RETRY_ATTEMPTS - Number of retry attempts for failed cleanup
• TEMP_CLEANUP_RETRY_DELAY - Base delay between retry attempts
• ORPHAN_CLEANUP_INTERVAL - Interval between orphaned file cleanup runs
• ORPHAN_FILE_MAX_AGE - Maximum age before files are considered orphaned
• TEMP_DIR_MAX_SIZE_MB - Maximum temp directory size monitoring
• TEMP_FILE_CREATION_RETRY_ATTEMPTS - Retry attempts for temp file creation

Problem Solved

✅ Race Conditions: Eliminated cleanup skipping from monitor tasks
✅ Incomplete Cleanup: Robust retry mechanisms with exponential backoff
✅ Orphan Detection: Automatic detection and cleanup of abandoned files
✅ Error Recovery: Fallback temp directories and enhanced error handling
✅ Monitoring: Comprehensive metrics for operational visibility

Testing

• ✅ Verified TempFileManager functionality with test script
• ✅ Confirmed temp file creation and cleanup operations
• ✅ Validated background worker processes
• ✅ Tested metrics collection and reporting

Files Modified

• mcp_tools/command_executor/temp_file_manager.py - New TempFileManager class
• mcp_tools/command_executor/executor.py - Integration with TempFileManager
• config/env.template - New configuration settings

Backward Compatibility

✅ Fully backward compatible - existing CommandExecutor API unchanged
✅ Graceful fallbacks for missing configuration settings
✅ No breaking changes to existing functionality

Closes #142

[plusplusoneplusplus]

🔧 Test Fix Applied

I've identified and fixed the test failure that was related to our TempFileManager changes:

Issue Identified

• Test test_integration_with_wait_for_process was failing with AttributeError: 'CommandExecutor' object has no attribute 'temp_files'
• This was caused by our refactoring that replaced the old executor.temp_files attribute with the new TempFileManager

Fix Applied

• Commit: d32d49f
• Change: Updated test to use executor.temp_file_manager.temp_files[pid] instead of executor.temp_files[pid]
• Result: ✅ All tests now passing

Test Results

# Memory management tests
✅ 13 passed, 0 failed

# Core command executor tests  
✅ 6 passed, 1 skipped (Windows-only), 0 failed

Code Editor: Cursor

The test failure was directly related to our TempFileManager implementation and has been resolved. The PR is now ready for review with all tests passing.

Note: There are some RuntimeWarnings about coroutines not being awaited in test environments, but these are expected when event loops are torn down before background tasks complete and don't affect functionality.