Start adding editor, fix up sidebar styling

src/app/app.config.ts

@@ -1,4 +1,5 @@
 import {
+  APP_INITIALIZER,
   ApplicationConfig,
   provideExperimentalZonelessChangeDetection,
 } from '@angular/core';
@@ -6,11 +7,39 @@ import { provideRouter } from '@angular/router';
 
 import { provideAnimationsAsync } from '@angular/platform-browser/animations/async';
 import { routes } from './app.routes';
+import hljs from 'highlight.js/lib/core';
+import json from 'highlight.js/lib/languages/json';
+import {
+  MAT_ICON_DEFAULT_OPTIONS,
+  MatIconRegistry,
+} from '@angular/material/icon';
 
 export const appConfig: ApplicationConfig = {
   providers: [
     provideExperimentalZonelessChangeDetection(),
     provideRouter(routes),
     provideAnimationsAsync(),
+    {
+      provide: APP_INITIALIZER,
+      useValue: () => {
+        hljs.registerLanguage('json', json);
+      },
+      multi: true,
+    },
+    {
+      provide: APP_INITIALIZER,
+      useFactory: (iconRegistry: MatIconRegistry) => () => {
+        iconRegistry.registerFontClassAlias(
+          'material-symbols-rounded',
+          'material-symbols-rounded'
+        );
+      },
+      deps: [MatIconRegistry],
+      multi: true,
+    },
+    {
+      provide: MAT_ICON_DEFAULT_OPTIONS,
+      useValue: { fontSet: 'material-symbols-rounded' },
+    },
   ],
 };