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/mobile-native/src/lib.rs

@@ -1,6 +1,8 @@
 mod error;
 mod ffi_types;
 mod payload_codec;
+#[cfg(any(target_os = "android", target_os = "ios"))]
+mod preview;
 mod storage;
 #[cfg(test)]
 mod tests;
@@ -14,6 +16,8 @@ pub use error::UniffiError;
 pub use ffi_types::{
   Blob, BlockInfo, CrawlResult, DocClock, DocRecord, DocUpdate, ListedBlob, MatchRange, SearchHit, SetBlob,
 };
+#[cfg(any(target_os = "android", target_os = "ios"))]
+pub use preview::{render_mermaid_preview_svg, render_typst_preview_svg};
 pub use storage::{DocStoragePool, new_doc_storage_pool};
 
 uniffi::setup_scaffolding!("affine_mobile_native");