Add report logos and configurable folder scan depth

Report branding (top-left MSP logo, top-right client logo):
- Add MspLogo to AppSettings; client logo already on TenantProfile
- IUserSessionService.CurrentBranding composes MSP + active profile logo
- New reusable LogoUpload component (InputFile -> base64 LogoData, 512KB cap)
- MSP logo upload in Settings; optional client logo in profile create/edit
- Wire ReportBranding into all 6 HTML export pages
- Fix EditProfile dropping ClientLogo on edit

Storage metrics: expose folder scan depth (0-20) in scan options UI,
passed to existing StorageScanOptions.FolderDepth recursion.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Core/Models/AppSettings.cs

@@ -6,4 +6,7 @@ public class AppSettings
     public string Lang { get; set; } = "en";
     public bool AutoTakeOwnership { get; set; } = false;
     public string Theme { get; set; } = "System";
+
+    /// <summary>MSP logo shown top-left on exported reports. Null = none.</summary>
+    public LogoData? MspLogo { get; set; }
 }