feat(save-attachments): scope folder list to the selected case

The folder dropdown was showing every DocumentFolder in EspoCRM (global
list). The user expected "folders that exist in THIS case" — only the
folders already in use for the chosen case's documents.

Change: when the user picks a case in the SaveAttachments dialog, the
folder list refreshes by walking
  GET /Case/{id}/documents?select=id,folderId,folderName&maxSize=200
and deduping the folderId values it finds. EspoCRM denormalizes
folderName onto Document, so no second lookup is needed.

If a case has no documents yet, the dropdown shows just the sentinel
"(בלי תיקייה)" — same default behavior as before, but no more
unrelated folders from other cases.

Files:
- Core: DocumentEntity gets FolderName; IEspoCrmClient and EspoCrmClient
  get ListFoldersUsedInCaseAsync(caseId)
- UI: SaveAttachmentsViewModel re-fetches on SelectedCase change
  (LoadFoldersForCaseAsync); AddInHost no longer calls the old
  LoadFoldersAsync.

Tests: 39 still passing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/OutlookAddin.Core/Models/DocumentEntity.cs

@@ -19,6 +19,9 @@ namespace MarcusLaw.OutlookAddin.Core.Models
         [JsonPropertyName("folderId")]
         public string? FolderId { get; set; }
 
+        [JsonPropertyName("folderName")]
+        public string? FolderName { get; set; }
+
         [JsonPropertyName("parentType")]
         public string? ParentType { get; set; }
 

src/OutlookAddin.Core/Services/EspoCrmClient.cs

@@ -267,6 +267,45 @@ namespace MarcusLaw.OutlookAddin.Core.Services
             }
         }
 
+        public async Task<List<DocumentFolder>> ListFoldersUsedInCaseAsync(string caseId, CancellationToken cancellationToken = default)
+        {
+            if (string.IsNullOrWhiteSpace(caseId)) return new List<DocumentFolder>();
+
+            // EspoCRM doesn't have a Case → DocumentFolder relationship by
+            // default — but it DOES expose all documents linked to the case
+            // via the related-records endpoint, and each document returns
+            // its folderId + folderName denormalized. We dedupe to surface
+            // the folders that are already in use for that case (the user's
+            // mental model: "תיקיות שיש בתיק").
+            var path =
+                "Case/" + Uri.EscapeDataString(caseId) + "/documents" +
+                "?select=" + Uri.EscapeDataString("id,folderId,folderName") +
+                "&maxSize=200";
+            try
+            {
+                var response = await GetJsonAsync<EspoListResponse<DocumentEntity>>(path, cancellationToken).ConfigureAwait(false);
+                var seen = new HashSet<string>(StringComparer.Ordinal);
+                var folders = new List<DocumentFolder>();
+                foreach (var doc in response.List)
+                {
+                    if (string.IsNullOrEmpty(doc.FolderId)) continue;
+                    if (!seen.Add(doc.FolderId!)) continue;
+                    folders.Add(new DocumentFolder
+                    {
+                        Id = doc.FolderId!,
+                        Name = string.IsNullOrWhiteSpace(doc.FolderName) ? doc.FolderId! : doc.FolderName!
+                    });
+                }
+                _logger.Information("ListFoldersUsedInCase({CaseId}) → {Count} distinct folders", caseId, folders.Count);
+                return folders;
+            }
+            catch (Exception ex)
+            {
+                _logger.Warning(ex, "ListFoldersUsedInCaseAsync({CaseId}) failed", caseId);
+                return new List<DocumentFolder>();
+            }
+        }
+
         public async Task<EspoListResponse<DocumentFolder>> ListDocumentFoldersAsync(CancellationToken cancellationToken = default)
         {
             try

src/OutlookAddin.Core/Services/IEspoCrmClient.cs

@@ -19,5 +19,6 @@ namespace MarcusLaw.OutlookAddin.Core.Services
         Task<AttachmentEntity> UploadAttachmentAsync(string fileName, string contentType, string base64Content, CancellationToken cancellationToken = default);
         Task<DocumentEntity> CreateDocumentAsync(string name, string attachmentFileId, string? parentType, string? parentId, string? folderId, CancellationToken cancellationToken = default);
         Task<EspoListResponse<DocumentFolder>> ListDocumentFoldersAsync(CancellationToken cancellationToken = default);
+        Task<System.Collections.Generic.List<DocumentFolder>> ListFoldersUsedInCaseAsync(string caseId, CancellationToken cancellationToken = default);
     }
 }

src/OutlookAddin.UI/ViewModels/SaveAttachmentsViewModel.cs

@@ -85,22 +85,6 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
             }
         }
 
-        public async Task LoadFoldersAsync(CancellationToken ct = default)
-        {
-            try
-            {
-                var result = await _client.ListDocumentFoldersAsync(ct).ConfigureAwait(true);
-                foreach (var folder in result.List)
-                {
-                    Folders.Add(folder);
-                }
-            }
-            catch (Exception ex)
-            {
-                _logger.Warning(ex, "SaveAttachmentsViewModel.LoadFoldersAsync failed");
-            }
-        }
-
         partial void OnSearchTextChanged(string value)
         {
             _searchCts?.Cancel();
@@ -111,6 +95,32 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
         partial void OnSelectedCaseChanged(CaseEntity? value)
         {
             SubmitCommand.NotifyCanExecuteChanged();
+            // Folders are scoped to the chosen case — refresh whenever the
+            // case selection changes.
+            _ = LoadFoldersForCaseAsync(value?.Id);
+        }
+
+        public async Task LoadFoldersForCaseAsync(string? caseId)
+        {
+            // Reset to the sentinel row first; we'll append folders below.
+            Folders.Clear();
+            Folders.Add(new DocumentFolder { Id = string.Empty, Name = "(בלי תיקייה)" });
+            SelectedFolder = Folders[0];
+
+            if (string.IsNullOrWhiteSpace(caseId)) return;
+
+            try
+            {
+                var folders = await _client.ListFoldersUsedInCaseAsync(caseId!).ConfigureAwait(true);
+                foreach (var folder in folders)
+                {
+                    Folders.Add(folder);
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.Warning(ex, "SaveAttachmentsViewModel.LoadFoldersForCaseAsync failed for {CaseId}", caseId);
+            }
         }
 
         private async Task SearchAsync(string query, CancellationToken ct)

src/OutlookAddin/Services/AddInHost.cs

@@ -482,8 +482,8 @@ namespace OutlookAddin.Services
             }
 
             var vm = new SaveAttachmentsViewModel(CrmClient!, Logger, envelope.Attachments);
-            // Best-effort folder list — failures already logged inside the VM.
+            // Folders are loaded lazily when the user picks a case — the
-            _ = vm.LoadFoldersAsync();
+            // sentinel "(בלי תיקייה)" row is already present.
 
             var dialog = new SaveAttachmentsDialog(vm);
             AttachOwnerToOutlook(dialog);