chore: Cleanup Access Layer

[Soap-141]

GitHub Issue: #

Proposed Changes

• Bug fix
• Feature
• Code style update (formatting)
• Refactoring (no functional changes, no api changes)
• Build or CI related changes
• Documentation content changes
• Other, please describe:

Description

Clean up the access layer by sealing classes and removing unused imports. I also made the authentication data classes as before (and adjusted places where needed based on those changes).

Impact on version

• Major
  • The template structure was changed.
• Minor
  • New functionalities were added.
• Patch
  • A bug in behavior was fixed.
  • Documentation was changed.

PR Checklist

Always applicable

No matter your changes, these checks always apply.

• Your conventional commits are aligned with the Impact on version section.
• Updated CHANGELOG.md.
  • Use the latest Major.Minor.X header if you do a Patch change.
  • Create a new Major.Minor.X header if you do a Minor or Major change.
  • If you create a new header, it aligns with the Impact on version section and matches what is generated in the build pipeline.
• Documentation files were updated according with the changes.
  • Update README.md and TemplateConfig.md if you made changes to templating.
  • Update AzurePipelines.md and APP_README.md if you made changes to pipelines.
  • Update Diagnostics.md if you made changes to diagnostic tools.
  • Update Architecture.md and its diagrams if you made architecture decisions or if you introduced new recipes.
  • ...and so forth: Make sure you update the documentation files associated to the recipes you changed. Review the topics by looking at the content of the doc/ folder.
• Images about the template are referenced from the wiki and added as images in this git.
• TODO comments are hints for next steps for users of the template and not planned work.

Contextual

Based on your changes these checks may not apply.

• Automated tests for the changes have been added/updated.
• Tested on all relevant platforms

Other information

Internal Issue (If applicable):

[Copilot]

Pull Request Overview

This PR cleans up the Access Layer by renaming repository classes to API clients, sealing classes, removing unused namespaces, and refactoring authentication data classes for improved consistency.

• Renames repositories to API clients (UserProfile, Posts) and seals classes.
• Removes unused import directives across several files.
• Refactors authentication token/data classes and adjusts related tests/code paths.

Reviewed Changes

Copilot reviewed 24 out of 25 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/app/ApplicationTemplate.Access/ApiClients/UserProfile/UserProfileApiClientMock.cs	Renamed and sealed UserProfile API client; adjusted constructor signature.
src/app/ApplicationTemplate.Access/ApiClients/UserProfile/IUserProfileApiClient.cs	Renamed interface and removed unused namespaces.
src/app/ApplicationTemplate.Access/ApiClients/Posts/PostsApiClientMock.cs	Renamed and sealed Posts API client; streamlined using directives.
src/app/ApplicationTemplate.Access/ApiClients/Posts/PostsApiClientException.cs	Added a new exception type for the posts API client.
src/app/ApplicationTemplate.Access/ApiClients/Posts/PostRepositoryException.cs and PostErrorResponse.cs	Removed legacy classes no longer needed after refactoring.
src/app/ApplicationTemplate.Access/ApiClients/Posts/IPostsApiClient.cs	Renamed interface and removed unused using directives.
src/app/ApplicationTemplate.Access/ApiClients/Posts/Data/PostData.cs	Sealed the record type for post data.
src/app/ApplicationTemplate.Access/ApiClients/Authentication/*	Refactored and relocated AuthenticationToken and AuthenticationData classes, updating to init-only properties and sealing classes.
CHANGELOG.md	Updated changelog to reflect the cleanup and renaming changes.

Files not reviewed (1)

• src/app/ApplicationTemplate.Access/ApplicationTemplate.Access.csproj: Language not supported