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/Services/IStorageService.cs

@@ -26,4 +26,16 @@ public interface IStorageService
         ClientContext ctx,
         IProgress<OperationProgress> progress,
         CancellationToken ct);
+
+    /// <summary>
+    /// Backfills StorageNodes that have zero TotalFileCount/TotalSizeBytes
+    /// by enumerating files per library via CamlQuery.
+    /// This works around the StorageMetrics API returning zeros when the
+    /// caller lacks sufficient permissions or metrics haven't been calculated.
+    /// </summary>
+    Task BackfillZeroNodesAsync(
+        ClientContext ctx,
+        IReadOnlyList<StorageNode> nodes,
+        IProgress<OperationProgress> progress,
+        CancellationToken ct);
 }