fix(script/jsx): cannot find preact hydration function

apps/client/src/services/frontend_script_api.ts

@@ -1,6 +1,5 @@
-import { dayjs } from "@triliumnext/commons";
-import { formatLogMessage } from "@triliumnext/commons";
-import { VNode } from "preact";
+import { dayjs, formatLogMessage } from "@triliumnext/commons";
+import { Fragment, h, VNode } from "preact";
 
 import appContext from "../components/app_context.js";
 import type Component from "../components/component.js";
@@ -467,12 +466,17 @@ export interface Api {
      */
     log(message: string | object): void;
 
+
+    // Preact support
     /**
      * Method that must be run for widget scripts that run on Preact, using JSX. The method just returns the same definition, reserved for future typechecking and perhaps validation purposes.
      *
      * @param definition the widget definition.
      */
     defineWidget(definition: WidgetDefinition): void;
+
+    h: typeof h;
+    Fragment: typeof Fragment;
 }
 
 export interface WidgetDefinition {
@@ -739,12 +743,16 @@ function FrontendScriptApi(this: Api, startNote: FNote, currentNote: FNote, orig
         this.logMessages[noteId].push(message);
         this.logSpacedUpdates[noteId].scheduleUpdate();
     };
+
+    // React support.
     this.defineWidget = (definition) => {
         return {
             type: "react-widget",
             ...definition
         };
     };
+    this.h = h;
+    this.Fragment = Fragment;
 }
 
 export default FrontendScriptApi as any as {