feat(menu): reorganize native menu bar with discoverable actions

Move Check for Updates into the macOS app menu and add Settings (Cmd+,),
Save (Cmd+S), Find (Cmd+F), chapter navigation, and a Help > Report an
Issue link. Route new menu actions through menu-action events and trim
duplicate editor keybindings.

src/export/typst.ts

@@ -20,7 +20,7 @@ const TRIM: Record<TrimSize, { w: string; h: string }> = {
   a5: { w: "148mm", h: "210mm" },
 };
 
-const INLINE_SPECIAL = /[\\#$*_`<>@~[\]]/g;
+const INLINE_SPECIAL = /[\\#$*_`<>@~()[\]]/g;
 const LINE_SEPARATORS = /[\n\r\v\f\u2028\u2029]+/g;
 
 function esc(text: string): string {