Commit MWS backend source tree

The ASP.NET Core solution (mws.api/mws.application/mws.domain/
mws.infrastructure) existed only as untracked working files. Adding
it to version control, plus a .gitignore for build output and local
tooling directories, so the CQRS/mediator refactor plan has a real
git history to branch and diff against.

mws.application/Documents/IDocumentService.cs

@@ -0,0 +1,14 @@
+using Mws.Application.Common;
+
+namespace Mws.Application.Documents;
+
+public interface IDocumentService
+{
+    Task<List<DocumentNodeDto>> GetTreeAsync(Guid userId, Guid projectId, CancellationToken ct = default);
+    Task<DocumentDto> GetAsync(Guid userId, Guid documentId, CancellationToken ct = default);
+    Task<DocumentDto> CreateAsync(Guid userId, Guid projectId, CreateDocumentRequest request, CancellationToken ct = default);
+    Task<DocumentDto> UpdateAsync(Guid userId, Guid documentId, UpdateDocumentRequest request, CancellationToken ct = default);
+    Task MoveAsync(Guid userId, Guid documentId, Guid? newParentId, CancellationToken ct = default);
+    Task DeleteAsync(Guid userId, Guid documentId, CancellationToken ct = default);
+    Task<List<DocumentNodeDto>> SearchAsync(Guid userId, string term, CancellationToken ct = default);
+}