Refactor LogTabWindow and extract logic that is not needed in the GUI

[Hirogen]

This pull request introduces several improvements and fixes across the codebase, focusing on enhancing test coverage, refining interface documentation, improving null handling, and updating dependencies. The most significant changes are the addition of comprehensive integration and unit tests for LogWindowCoordinator and LogWindow, interface and documentation cleanups, and minor adjustments to test expectations and SDK versions.

New and Improved Test Coverage:

• Added a new integration test suite for LogWindowCoordinator and LogWindow in LogWindowCoordinatorIntegrationTests, verifying event subscriptions, property delegation, and proper resource cleanup. ([src/LogExpert.Tests/Controls/LogWindowCoordinatorIntegrationTests.csR1-R146])
• Introduced a comprehensive unit test suite for LogWindowCoordinator in LogWindowCoordinatorTests, covering highlight group resolution, columnizer resolution, shared state, and delegation logic. ([src/LogExpert.Tests/Services/LogWindowCoordinatorTests.csR1-R300])

Interface, Documentation, and Usability Improvements:

• Updated the IContextMenuEntry interface: improved parameter documentation for GetMenuText, removed obsolete method overloads, and clarified remarks about null handling and parameter expectations. [1]], [2]])
• Cleaned up the ILogWindow interface by removing a redundant summary and ensuring clarity in method documentation. ([src/LogExpert.Core/Interfaces/ILogWindow.csL150-L164])

Bug Fixes and Robustness:

• Improved null handling in LogfileReader by ensuring that asynchronous methods return Task.FromResult<ILogLineMemory>(null) instead of null, preventing potential runtime issues. [1]], [2]])
• Added a CopyFrom method to the SearchParams class for safe copying of search parameters between instances, with null checks. ([src/LogExpert.Core/Entities/SearchParams.csR24-R38])

Test Timeout Adjustments:

• Increased timeout thresholds in ProjectFileValidatorTests to accommodate slower environments and reduce test flakiness. [1]], [2]])

Dependency Updates:

• Updated the .NET SDK version in global.json from 10.0.100 to 10.0.200. ([global.jsonL3-R3])

Minor Cleanups:

• Removed a stale TODO comment from the Column class. ([src/ColumnizerLib/Column.csL5])

These changes collectively improve reliability, maintainability, and test coverage of the codebase.