Convert Documents module to MediatR commands/queries

Replaces IDocumentService/DocumentService. The permission-check and
descendant-deletion logic moves to a shared DocumentAccess static
helper used by all seven handlers.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

mws.api/Controllers/DocumentsController.cs

@@ -1,3 +1,4 @@
+using MediatR;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Mws.Application.Documents;
@@ -7,50 +8,50 @@ namespace Mws.Api.Controllers;
 [ApiController]
 [Route("api")]
 [Authorize]
-public class DocumentsController(IDocumentService documentService) : ControllerBase
+public class DocumentsController(ISender sender) : ControllerBase
 {
     [HttpGet("documents/search")]
     public async Task<ActionResult<List<DocumentNodeDto>>> Search([FromQuery] string? q, CancellationToken ct)
     {
-        return Ok(await documentService.SearchAsync(User.GetUserId(), q ?? string.Empty, ct));
+        return Ok(await sender.Send(new SearchDocumentsQuery(User.GetUserId(), q ?? string.Empty), ct));
     }
 
     [HttpGet("projects/{projectId:guid}/documents")]
     public async Task<ActionResult<List<DocumentNodeDto>>> GetTree(Guid projectId, CancellationToken ct)
     {
-        return Ok(await documentService.GetTreeAsync(User.GetUserId(), projectId, ct));
+        return Ok(await sender.Send(new GetDocumentTreeQuery(User.GetUserId(), projectId), ct));
     }
 
     [HttpPost("projects/{projectId:guid}/documents")]
     public async Task<ActionResult<DocumentDto>> Create(Guid projectId, [FromBody] CreateDocumentRequest request, CancellationToken ct)
     {
-        var result = await documentService.CreateAsync(User.GetUserId(), projectId, request, ct);
+        var result = await sender.Send(new CreateDocumentCommand(User.GetUserId(), projectId, request), ct);
         return CreatedAtAction(nameof(Get), new { id = result.Id }, result);
     }
 
     [HttpGet("documents/{id:guid}")]
     public async Task<ActionResult<DocumentDto>> Get(Guid id, CancellationToken ct)
     {
-        return Ok(await documentService.GetAsync(User.GetUserId(), id, ct));
+        return Ok(await sender.Send(new GetDocumentQuery(User.GetUserId(), id), ct));
     }
 
     [HttpPut("documents/{id:guid}")]
     public async Task<ActionResult<DocumentDto>> Update(Guid id, [FromBody] UpdateDocumentRequest request, CancellationToken ct)
     {
-        return Ok(await documentService.UpdateAsync(User.GetUserId(), id, request, ct));
+        return Ok(await sender.Send(new UpdateDocumentCommand(User.GetUserId(), id, request), ct));
     }
 
     [HttpPut("documents/{id:guid}/move")]
     public async Task<ActionResult<DocumentDto>> Move(Guid id, [FromBody] MoveDocumentRequest request, CancellationToken ct)
     {
-        await documentService.MoveAsync(User.GetUserId(), id, request.NewParentId, ct);
-        return Ok(await documentService.GetAsync(User.GetUserId(), id, ct));
+        await sender.Send(new MoveDocumentCommand(User.GetUserId(), id, request.NewParentId), ct);
+        return Ok(await sender.Send(new GetDocumentQuery(User.GetUserId(), id), ct));
     }
 
     [HttpDelete("documents/{id:guid}")]
     public async Task<IActionResult> Delete(Guid id, CancellationToken ct)
     {
-        await documentService.DeleteAsync(User.GetUserId(), id, ct);
+        await sender.Send(new DeleteDocumentCommand(User.GetUserId(), id), ct);
         return NoContent();
     }
-}
+}