fix(central-ui): resolve CentralUI-020..025 — auth-ping idle logout, DebugView race, push-handler disposal guard, JS-interop catch narrowing, claim-constant helper, SessionExpiry tests

src/ScadaLink.CentralUI/Components/Pages/Deployment/InstanceCreate.razor

@@ -157,9 +157,8 @@
 
     private void GoBack() => NavigationManager.NavigateTo("/deployment/topology");
 
-    private async Task<string> GetCurrentUserAsync()
-    {
-        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
-        return authState.User.FindFirst("Username")?.Value ?? "unknown";
-    }
+    // CentralUI-024: delegates to the shared helper so the claim type stays
+    // resolved through JwtTokenService rather than a duplicated magic string.
+    private Task<string> GetCurrentUserAsync()
+        => AuthStateProvider.GetCurrentUsernameAsync();
 }