add alert

projects/nshmp-apps/src/app/designmaps/rtgm/components/plots/plots.component.html

 <nshmp-lib-ng-plots-container>
+  <nshmp-lib-ng-alert>
+    This application currently performs the RTGM calculation for a single
+    intensity measure (IM) hazard curve at a time. For bulk calculation of RTGMs
+    for a larger number of IM hazard curves, please refer to
+    <a target="_blank">https://earthquake.usgs.gov/ws/nshmp/designmaps/rtgm/</a>
+    or
+    <a target="_blank">https://code.usgs.gov/ghsc/erp/erp-rtgm-calculator</a>
+  </nshmp-lib-ng-alert>
+
   <mat-accordion multi>
     @for (plot of plots(); track $index) {
       <mat-expansion-panel expanded>

projects/nshmp-apps/src/app/designmaps/rtgm/components/plots/plots.component.ts

 import {Component, computed, OnDestroy, OnInit} from '@angular/core';
 import {MatDivider} from '@angular/material/divider';
 import {MatExpansionModule} from '@angular/material/expansion';
-import {NshmpLibNgAppMetadataComponent} from '@ghsc/nshmp-lib-ng/nshmp';
+import {
+  NshmpLibNgAlertComponent,
+  NshmpLibNgAppMetadataComponent,
+} from '@ghsc/nshmp-lib-ng/nshmp';
 import {
   NshmpLibNgPlotComponent,
   NshmpLibNgPlotsContainerComponent,
@@ -18,6 +21,7 @@ import {RtgmSummaryComponent} from '../rtgm-summary/rtgm-summary.component';
     NshmpLibNgPlotsContainerComponent,
     NshmpLibNgPlotComponent,
     NshmpLibNgAppMetadataComponent,
+    NshmpLibNgAlertComponent,
     MatExpansionModule,
     MatDivider,
     ParameterSummaryComponent,