feat(scripts): ScriptAlarm.IsMesReportable + Alarms.MesReportableAsync() mirrored on both compile surfaces

Claude-Session: https://claude.ai/code/session_01Y5ef34iUUMjmwnMpL9xgmB

src/ZB.MOM.WW.ScadaBridge.CentralUI/ScriptAnalysis/SandboxScriptHost.cs

@@ -161,6 +161,18 @@ public class SandboxAlarmsAccessor
             "Alarms.CurrentAsync() reads the site Instance Actor's live alarm conditions, " +
             "which aren't available in the central Test Run sandbox — deploy to a site to " +
             "exercise alarm-reading scripts.");
+
+    /// <summary>
+    /// Mirrors <c>AlarmsAccessor.MesReportableAsync</c> for compile parity; unsupported at
+    /// run time in the central Test Run sandbox.
+    /// </summary>
+    /// <param name="cancellationToken">Token used to cancel the read (unused in the sandbox).</param>
+    /// <returns>Never returns; always throws <see cref="ScriptSandboxException"/> in the sandbox.</returns>
+    public Task<IReadOnlyList<ScriptAlarm>> MesReportableAsync(CancellationToken cancellationToken = default)
+        => throw new ScriptSandboxException(
+            "Alarms.MesReportableAsync() reads the site Instance Actor's live alarm conditions, " +
+            "which aren't available in the central Test Run sandbox — deploy to a site to " +
+            "exercise alarm-reading scripts.");
 }
 
 /// <summary>