Added fun preference section, added avali font toggle

src/lib/extension/preferences/FunPreferences.ts

@@ -0,0 +1,16 @@
+import CacheablePreferences, { PreferenceField, type WithFields } from "$lib/extension/base/CacheablePreferences";
+
+interface FunPreferencesFields {
+  useAvaliFont: boolean;
+}
+
+export default class FunPreferences extends CacheablePreferences<FunPreferencesFields> implements WithFields<FunPreferencesFields> {
+  constructor() {
+    super('fun');
+  }
+
+  readonly useAvaliFont = new PreferenceField(this, {
+    field: "useAvaliFont",
+    defaultValue: false,
+  });
+}