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/UserAccessAuditService.cs

@@ -114,7 +114,7 @@ public class UserAccessAuditService : IUserAccessAuditService
 
                     yield return new UserAccessEntry(
                         UserDisplayName: displayName,
-                        UserLogin: login,
+                        UserLogin: StripClaimsPrefix(login),
                         SiteUrl: site.Url,
                         SiteTitle: site.Title,
                         ObjectType: entry.ObjectType,
@@ -133,6 +133,16 @@ public class UserAccessAuditService : IUserAccessAuditService
     /// <summary>
     /// Classifies a PermissionEntry into Direct, Group, or Inherited access type.
     /// </summary>
+    /// <summary>
+    /// Removes SharePoint claims prefixes like "i:0#.f|membership|" so the
+    /// UI displays a plain email instead of the full claim string.
+    /// </summary>
+    private static string StripClaimsPrefix(string login)
+    {
+        int pipe = login.LastIndexOf('|');
+        return pipe >= 0 ? login[(pipe + 1)..] : login;
+    }
+
     private static AccessType ClassifyAccessType(PermissionEntry entry)
     {
         // Inherited: object does not have unique permissions