chore: archive v1.1 Enhanced Reports milestone

v1.1 shipped with 4 phases (25 plans), 10/10 requirements complete:
- Global site selection (toolbar picker, all tabs consume)
- User access audit (Graph people-picker, direct/group/inherited)
- Simplified permissions (plain-language labels, risk levels, detail toggle)
- Storage visualization (LiveCharts2 pie/donut + bar charts)

Post-phase polish: centralized site selection (removed per-tab pickers),
claims prefix stripping, StorageMetrics backfill, chart tooltip fix,
summary stats in app + HTML exports.

205 tests passing, 10,484 LOC.

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

SharepointToolbox/Views/Tabs/FolderStructureView.xaml

@@ -4,11 +4,7 @@
              xmlns:loc="clr-namespace:SharepointToolbox.Localization">
     <DockPanel Margin="10">
         <StackPanel DockPanel.Dock="Left" Width="280" Margin="0,0,10,0">
-            <!-- Site URL and Library inputs -->
-            <TextBlock Text="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[folderstruct.siteurl]}"
-                       Margin="0,0,0,3" />
-            <TextBox Text="{Binding SiteUrl, UpdateSourceTrigger=PropertyChanged}" Margin="0,0,0,10" />
-
+            <!-- Library input -->
             <TextBlock Text="{Binding Source={x:Static loc:TranslationSource.Instance}, Path=[folderstruct.library]}"
                        Margin="0,0,0,3" />
             <TextBox Text="{Binding LibraryTitle, UpdateSourceTrigger=PropertyChanged}" Margin="0,0,0,10" />