feat(editor): migrate typst mermaid to native (#14499)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Native/WASM Mermaid and Typst SVG preview rendering on desktop and
mobile, plus cross-platform Preview plugin integrations.

* **Improvements**
* Centralized, sanitized rendering bridge with automatic Typst
font-directory handling and configurable native renderer selection.
* More consistent and robust error serialization and worker-backed
preview flows for improved stability and performance.

* **Tests**
* Extensive unit and integration tests for preview rendering, font
discovery, sanitization, and error serialization.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/apps/electron/src/helper/exposed.ts

@@ -1,5 +1,6 @@
 import { dialogHandlers } from './dialog';
 import { dbEventsV1, dbHandlersV1, nbstoreHandlers } from './nbstore';
+import { previewHandlers } from './preview';
 import { provideExposed } from './provide';
 import { workspaceEvents, workspaceHandlers } from './workspace';
 
@@ -8,6 +9,7 @@ export const handlers = {
   nbstore: nbstoreHandlers,
   workspace: workspaceHandlers,
   dialog: dialogHandlers,
+  preview: previewHandlers,
 };
 
 export const events = {