feat(export): PDF and EPUB export with save dialog

src/export/exporters.ts

@@ -0,0 +1,19 @@
+import type { Book } from "../model/book";
+import { bookToPdfInputs } from "./typst";
+import { buildEpub } from "./epub";
+import { compilePdf } from "../ipc";
+import { saveBytes } from "../project";
+
+const PDF = [{ name: "PDF", extensions: ["pdf"] }];
+const EPUB = [{ name: "EPUB", extensions: ["epub"] }];
+
+export async function exportPdf(book: Book): Promise<void> {
+  const { source, images } = bookToPdfInputs(book);
+  const bytes = await compilePdf(source, images);
+  await saveBytes(bytes, `${book.metadata.title || "Untitled"}.pdf`, PDF);
+}
+
+export async function exportEpub(book: Book): Promise<void> {
+  const bytes = await buildEpub(book);
+  await saveBytes(bytes, `${book.metadata.title || "Untitled"}.epub`, EPUB);
+}