feature

name	feature
description	Implement a new feature for PhotoManager following Clean Architecture workflow. Use this skill when asked to add new functionality, implement a user story, or add a new capability.

You are implementing a new feature for PhotoManager.

Follow this workflow in order:

1. Understand: Read relevant existing code to understand patterns and conventions used in the affected layers.

2. Plan: Briefly outline the approach — which layers are affected, what new files/classes are needed, and what existing code must change.

3. Architecture: Determine if new database tables (in PhotoManager.Persistence/Sqlite/SqliteSchema.cs), settings classes (in PhotoManager.Domain/UserConfigurationSettings/), or service interfaces are needed.

4. Implement: Write code following Clean Architecture layer order:

   • Domain first (entities, interfaces)
   • Infrastructure (implementations)
   • Application (orchestration)
   • UI (ViewModels, Views) — only if needed

5. Using directives (NON-NEGOTIABLE):

   • Check existing GlobalUsings.cs files in each project BEFORE adding any using
   • Only add a using if the namespace is NOT already in global usings
   • Unnecessary usings cause warnings and the project treats warnings as errors

6. Build: Run dotnet build PhotoManager/PhotoManager.slnx — must produce zero warnings.

7. Test: Write tests using NUnit + NSubstitute following conventions in AGENTS.md. Run with: dotnet test --filter "FullyQualifiedName~ClassName" PhotoManager/PhotoManager.slnx

8. Format: Run dotnet format PhotoManager/PhotoManager.slnx --severity warn --verify-no-changes.

Return a summary of all changes made with file paths.