fix(centralui): enforce site scoping on AlarmSummary — filter site list + deny out-of-scope alarm fetches, mirroring DebugView (arch-review 2026-08-19 P6-2 High)

AlarmSummary.razor was gated RequireDeployment but never consulted
SiteScopeService: the site picker listed every site unfiltered and
GetSiteAlarmsAsync ran for whatever siteId the onchange event carried,
so a Deployer scoped to one site could watch any site's live alarms
(including CurrentValue/LimitValue process data). The page was missed
by the ad0100f2 scoping survey.

Fix mirrors EventLogs.razor/DebugView.razor: OnInitializedAsync filters
_sites through SiteScope.FilterSitesAsync, and both the site-change
handler and RefreshAsync (the shared fetch path used by the manual
refresh button and the 15s poll timer) independently re-check the
selected site against the filtered list before ever calling
AlarmSummaryService, denying/resetting an out-of-scope id rather than
merely hiding it from the dropdown.

Tests: bUnit render tests added to AlarmSummaryRenderTests.cs proving
(1) a scoped Deployer's picker omits the out-of-scope site and (2) a
forged out-of-scope onchange value is denied — no row renders and
GetSiteAlarmsAsync is never called for that site. AlarmSummaryVirtualizeTests.cs
updated to register the now-required SiteScopeService.

tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryVirtualizeTests.cs

@@ -49,6 +49,7 @@ public class AlarmSummaryVirtualizeTests : BunitContext
             }));
         Services.AddSingleton(_siteRepo);
         Services.AddSingleton<ISiteAlarmLiveCache>(new InertLiveCache());
+        Services.AddScoped<ZB.MOM.WW.ScadaBridge.CentralUI.Auth.SiteScopeService>();
 
         var claims = new[]
         {