Refactoring: Added File Operation Service, for all File related stuff, fixed White / Black Lines when Buffers could not be found

[Hirogen]

This pull request introduces several improvements and refactorings to the log file buffer management, UI error handling, and file operation abstractions. The most significant changes include the addition of a new IFileOperationService interface to centralize file/tab operations, enhancements to the log buffer eviction process for better memory management, improved error handling in the UI for missing log lines, and updates to logging for better diagnostics.

File Operation Service Abstraction:

• Introduced a new IFileOperationService interface as a centralized facade for all file loading, tab creation, history management, and related operations. This abstraction is designed for future extensibility and clearer separation of concerns.
• Added FileOpenedEventArgs to carry detailed context when a file tab is created, supporting richer event-driven UI updates.
• Updated unit tests to mock and inject the new IFileOperationService, ensuring test coverage and compatibility. [1] [2]

Log Buffer Memory Management:

• Added an EvictContent method to LogBuffer, which clears the buffer's content to free memory but preserves metadata for efficient buffer lookup and reloading from disk. This helps optimize memory usage without losing buffer tracking.
• Updated the LRU cache garbage collection logic to use EvictContent instead of returning buffers to the pool prematurely, preventing accidental loss of buffer metadata.
• Improved the ClearLines method in LogBuffer to ensure proper initialization and clearing, and to reset debug tracking in debug builds.

UI and Logging Improvements:

• Enhanced the CellPainting method in the log window UI to gracefully handle missing log lines by painting empty cells and logging a warning, preventing rendering issues.
• Updated logging in GetLogLineMemoryWithWait to provide clearer diagnostics when fast-fail mode is triggered, aiding in debugging and support.

Minor Cleanups:

• Removed unused or redundant fields and comments from PositionAwareStreamReaderSystem for code clarity. [1] [2] [3]
• Improved XML documentation comments for readability and maintainability in various files. [1] [2]
• Cleaned up obsolete commented-out code in the log window reload logic.