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/android/src/plugins/preview/definitions.ts

@@ -0,0 +1,16 @@
+export interface PreviewPlugin {
+  renderMermaidSvg(options: {
+    code: string;
+    options?: {
+      theme?: string;
+      fontFamily?: string;
+      fontSize?: number;
+    };
+  }): Promise<{ svg: string }>;
+  renderTypstSvg(options: {
+    code: string;
+    options?: {
+      fontUrls?: string[];
+    };
+  }): Promise<{ svg: string }>;
+}

packages/frontend/apps/android/src/plugins/preview/index.ts

@@ -0,0 +1,8 @@
+import { registerPlugin } from '@capacitor/core';
+
+import type { PreviewPlugin } from './definitions';
+
+const Preview = registerPlugin<PreviewPlugin>('Preview');
+
+export * from './definitions';
+export { Preview };