docs(13-02): complete User Directory ViewModel plan

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.planning/phases/13-user-directory-viewmodel/13-02-SUMMARY.md

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+---
+phase: 13-user-directory-viewmodel
+plan: 02
+subsystem: viewmodel
+tags: [wpf, mvvm, user-directory, icollectionview, csharp]
+
+requires:
+  - phase: 13-user-directory-viewmodel
+    plan: 01
+    provides: IGraphUserDirectoryService with includeGuests param, GraphDirectoryUser with UserType
+provides:
+  - Directory browse mode in UserAccessAuditViewModel with load, filter, sort, cancel
+  - ICollectionView for directory users with member/guest and text filtering
+  - 16 unit tests for directory browse behavior
+affects:
+  - SharepointToolbox/ViewModels/Tabs/UserAccessAuditViewModel.cs
+  - SharepointToolbox.Tests/ViewModels/UserAccessAuditViewModelDirectoryTests.cs
+
+tech-stack:
+  added: []
+  patterns:
+    - ICollectionView with SortDescription and Filter predicate for directory users
+    - Separate CancellationTokenSource for directory load (independent from base class CTS)
+    - Optional constructor parameter for testability (IGraphUserDirectoryService?)
+
+key-files:
+  created:
+    - SharepointToolbox.Tests/ViewModels/UserAccessAuditViewModelDirectoryTests.cs
+  modified:
+    - SharepointToolbox/ViewModels/Tabs/UserAccessAuditViewModel.cs
+
+key-decisions:
+  - IGraphUserDirectoryService injected as optional param in test constructor to preserve backward compat
+  - Directory always fetches with includeGuests=true from Graph; member/guest filtering is in-memory via ICollectionView
+  - Separate _directoryCts field for directory load cancellation (not sharing base class _cts)
+  - No App.xaml.cs change needed — DI auto-resolves IGraphUserDirectoryService for UserAccessAuditViewModel
+
+metrics:
+  duration: 261s
+  completed: "2026-04-08T14:08:05Z"
+  tasks_completed: 4
+  tasks_total: 4
+  tests_added: 16
+  tests_passing: 24
+  files_changed: 2
+---
+
+# Phase 13 Plan 02: User Directory ViewModel Summary
+
+Directory browse mode with paginated Graph load, member/guest toggle filter, text search across 4 fields, and DisplayName-sorted ICollectionView -- all testable without WPF View layer.
+
+## What Was Done
+
+### Task 1: Inject IGraphUserDirectoryService into ViewModel
+- Added `_graphUserDirectoryService` field to `UserAccessAuditViewModel`
+- Added required parameter to full (DI) constructor after `brandingService`
+- Added optional parameter to test constructor for backward compatibility
+- Verified DI auto-resolves via existing `services.AddTransient<UserAccessAuditViewModel>()` registration
+
+### Task 2: Add directory browse mode properties and commands
+- Added 6 observable properties: `IsBrowseMode`, `DirectoryUsers`, `IsLoadingDirectory`, `DirectoryLoadStatus`, `IncludeGuests`, `DirectoryFilterText`
+- Added `DirectoryUserCount` computed property reflecting filtered view count
+- Added `DirectoryUsersView` (ICollectionView) with default SortDescription on DisplayName ascending
+- Added `LoadDirectoryCommand` (IAsyncRelayCommand) and `CancelDirectoryLoadCommand` (RelayCommand)
+- Initialized CollectionView and commands in both constructors
+- Added change handlers: `OnIncludeGuestsChanged`, `OnDirectoryFilterTextChanged`, `OnIsLoadingDirectoryChanged`
+
+### Task 3: Implement LoadDirectoryAsync, filter predicate, tenant switch cleanup
+- `LoadDirectoryAsync`: validates service/profile, creates CTS, calls GetUsersAsync with progress reporting, populates on UI thread, handles cancel/error
+- `DirectoryFilterPredicate`: filters by IncludeGuests (UserType=="Member") then by text match on DisplayName, UPN, Department, JobTitle
+- `PopulateDirectory` helper: clears and repopulates collection, refreshes view
+- `OnTenantSwitched`: cancels directory CTS, clears DirectoryUsers, resets all directory state
+- Exposed `TestLoadDirectoryAsync()` internal method for test access
+
+### Task 4: Write comprehensive tests (16 tests)
+- Created `UserAccessAuditViewModelDirectoryTests.cs` with helper factories
+- Tests cover: defaults, load populates, progress status, no-profile guard, cancellation, member/guest filtering, text filtering (DisplayName, Department, JobTitle), sort order, tenant switch reset, filtered count, search mode regression
+
+## Deviations from Plan
+
+None -- plan executed exactly as written.
+
+## Verification
+
+- `dotnet build --no-restore -warnaserror`: PASSED (0 warnings, 0 errors)
+- `dotnet test --filter "FullyQualifiedName~UserAccessAuditViewModel"`: 24/24 PASSED (8 existing + 16 new)
+
+## Commits
+
+| Hash | Message |
+|------|---------|
+| 4ba4de6 | feat(13-02): add directory browse mode with paginated load, member/guest filter, and sortable ICollectionView |