Misc fixes and unit test additions

[emgarten]

• Misc fixes and unit test additions

[Copilot]

Pull Request Overview

This PR introduces multiple miscellaneous fixes along with comprehensive unit test additions to improve code quality and maintainability across the SleetLib project.

• Added new unit tests covering utility methods, configuration commands, and file system behaviors.
• Improved asynchronous handling by adding ConfigureAwait(false) calls in various async methods.
• Enhanced file upload functionality by introducing proper stream disposal using try–finally patterns.

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test/SleetLib.Tests/PathUtilityTests.cs	Adds unit tests for GetFullPathWithoutExtension functionality
test/SleetLib.Tests/FileSystemFactoryTests.cs	Adds tests for various file system creation scenarios and error cases
test/SleetLib.Tests/FeedRequirementsTests.cs	Adds unit tests to verify default and settable properties of FeedRequirements
test/SleetLib.Tests/FeedCapabilityTests.cs	Adds tests ensuring correct parsing and formatting in FeedCapability
test/SleetLib.Tests/ExtensionsTests.cs	Adds tests to validate extension methods behavior and data conversion
test/SleetLib.Tests/CreateConfigCommandTests.cs	Adds tests for creating and validating configuration files
src/SleetLib/TemplateUtility.cs	Updates async stream reading by adding ConfigureAwait(false)
src/SleetLib/FileSystem/AzureFile.cs	Enhances stream disposal handling in the Azure file upload process
src/SleetLib/FileSystem/AmazonS3File.cs	Enhances stream disposal handling in the Amazon S3 file upload process
src/SleetLib/ExternalSearchHandler.cs	Ensures proper async patterns with ConfigureAwait(false) in search URI update
src/SleetLib/AssemblyVersionHelper.cs	Improves thread safety in version caching using double-check locking
src/Sleet/Program.cs	Converts Main method to asynchronous to better support async operations