Renaming for a less verbose API; hooking up a missed option

[tarrball]

Pull Request Overview

This PR implements a major API simplification by removing verbose "GuardianApi" prefixes from class and enum names, making the API more concise and user-friendly. The changes also introduce a previously missing ShowRights option and update the version to 0.5.0-alpha.

• Renamed all options classes to shorter names (e.g., GuardianApiContentSearchOptions → SearchOptions)
• Renamed all enums with cleaner names (e.g., GuardianApiContentOrderBy → ContentOrder)
• Added missing ShowRights functionality with ContentRight enum

Reviewed Changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
SearchOptions.cs	Renamed from GuardianApiContentSearchOptions and updated property types
PageOptions.cs	Renamed from GuardianApiContentPageOptions
OrderOptions.cs	Renamed class and property types to use new enum names
FilterOptions.cs	Renamed from GuardianApiContentFilterOptions
DateOptions.cs	Renamed from GuardianApiContentDateOptions
ContentType.cs	Renamed from GuardianApiContentOrderDate
ContentTag.cs	Renamed from GuardianApiContentShowTagsOption
ContentRight.cs	Renamed from GuardianApiContentShowRightsOption
ContentReference.cs	Renamed from GuardianApiContentShowReferencesOption to Reference
ContentOrder.cs	Renamed from GuardianApiContentOrderBy
ContentField.cs	Renamed from GuardianApiContentShowFieldsOption
ContentElement.cs	Renamed from GuardianApiContentShowElementsOption
AdditionalInformationOptions.cs	Renamed class and added missing ShowRights property
UrlParameterBuilder.cs	Updated method signatures and enum references to use new names
AdditionalInformationExtensions.cs	Updated extension methods to use new enum names
IGuardianApiClient.cs	Updated interface method signatures to use new option types
GuardianClient.csproj	Version bump and repository URL refinement
GuardianApiClient.cs	Updated method signatures, added debug logging, and code reorganization
TestBase.cs	Renamed ApiClient property to Client
SearchAsyncTests.cs	Updated to use new option class names and simplified assertions
GuardianApiClientIntegrationTests.cs	Updated to use new option class names and added new test method
GetItemAsyncTests.cs	Updated to use new option class names throughout test methods

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