refactor: migrate PDF export to desktop runtime abstraction

- Extract desktop-specific logic into src/services/desktop.ts
- Add runtime detection for Electron vs Tauri environments
- Simplify NoteEditor by delegating PDF export to desktop service
- Update printExport.ts to remove unused storage helpers
- Add Electron main process files in electron/ directory
- Update vite config and types for Electron integration
- Update .gitignore and package.json for Electron workflow

src/services/desktop.ts

@@ -0,0 +1,139 @@
+import {
+  buildPrintDocument,
+  PrintExportPayload,
+  PRINT_EXPORT_QUERY_PARAM,
+} from '../printExport';
+
+export interface DesktopMessageOptions {
+  title?: string;
+  kind?: 'info' | 'warning' | 'error';
+}
+
+interface ExportPdfResult {
+  canceled: boolean;
+  filePath?: string;
+}
+
+const isElectronRuntime = () =>
+  typeof window !== 'undefined' && typeof window.electronDesktop !== 'undefined';
+
+const isTauriRuntime = () =>
+  typeof window !== 'undefined' &&
+  (
+    typeof (window as Window & { __TAURI__?: unknown }).__TAURI__ !== 'undefined' ||
+    typeof (window as Window & { __TAURI_INTERNALS__?: unknown }).__TAURI_INTERNALS__ !== 'undefined'
+  );
+
+export const getDesktopRuntime = () => {
+  if (isElectronRuntime()) return 'electron';
+  if (isTauriRuntime()) return 'tauri';
+  return 'browser';
+};
+
+export const showDesktopMessage = async (
+  messageText: string,
+  options: DesktopMessageOptions = {}
+) => {
+  if (window.electronDesktop) {
+    await window.electronDesktop.showMessage({
+      message: messageText,
+      ...options,
+    });
+    return;
+  }
+
+  if (isTauriRuntime()) {
+    const { message } = await import('@tauri-apps/plugin-dialog');
+    await message(messageText, options);
+    return;
+  }
+
+  window.alert(messageText);
+};
+
+export const exportPdfDocument = async (
+  payload: PrintExportPayload
+): Promise<ExportPdfResult> => {
+  if (window.electronDesktop) {
+    return window.electronDesktop.exportPdf({
+      ...payload,
+      documentHtml: buildPrintDocument(payload),
+    });
+  }
+
+  if (isTauriRuntime()) {
+    await exportPdfDocumentWithTauri(payload);
+    return { canceled: false };
+  }
+
+  throw new Error('PDF export is only available in a desktop runtime.');
+};
+
+async function exportPdfDocumentWithTauri(payload: PrintExportPayload) {
+  const [{ emitTo, listen }, { WebviewWindow }] = await Promise.all([
+    import('@tauri-apps/api/event'),
+    import('@tauri-apps/api/webviewWindow'),
+  ]);
+
+  const jobId = `${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
+  const windowLabel = `print-export-${jobId}`;
+  let printWindow: any = null;
+  let unlistenReady: any = null;
+
+  try {
+    await new Promise<void>((resolve, reject) => {
+      let settled = false;
+      const timeoutId = window.setTimeout(() => {
+        if (settled) return;
+        settled = true;
+        unlistenReady?.();
+        reject(new Error('Print view initialization timed out.'));
+      }, 10000);
+
+      listen<{ jobId: string }>('print-export-ready', (event) => {
+        if (settled || event.payload.jobId !== jobId) return;
+
+        settled = true;
+        window.clearTimeout(timeoutId);
+        unlistenReady?.();
+
+        void emitTo(windowLabel, 'print-export-payload', payload)
+          .then(() => resolve())
+          .catch(reject);
+      })
+        .then((unlisten) => {
+          unlistenReady = unlisten;
+          printWindow = new WebviewWindow(windowLabel, {
+            url: `/?${PRINT_EXPORT_QUERY_PARAM}=${encodeURIComponent(jobId)}`,
+            title: 'Opening Print Dialog',
+            width: 960,
+            height: 1100,
+            center: true,
+            visible: true,
+            focus: true,
+            skipTaskbar: true,
+            resizable: false,
+            parent: 'main',
+          });
+
+          void printWindow.once('tauri://error', (event: { payload?: unknown }) => {
+            if (settled) return;
+            settled = true;
+            window.clearTimeout(timeoutId);
+            unlistenReady?.();
+            reject(new Error(String(event.payload ?? 'Failed to create print window.')));
+          });
+        })
+        .catch(reject);
+    });
+  } catch (error) {
+    if (printWindow) {
+      void printWindow.close().catch(() => undefined);
+    }
+    throw error;
+  } finally {
+    if (typeof unlistenReady === 'function') {
+      unlistenReady();
+    }
+  }
+}

src/services/runtimeFetch.ts

@@ -0,0 +1,155 @@
+interface ElectronHttpRequest {
+  url: string;
+  method?: string;
+  headers?: Record<string, string>;
+  bodyText?: string;
+  bodyBase64?: string;
+}
+
+interface ElectronHttpResponse {
+  ok: boolean;
+  status: number;
+  statusText: string;
+  headers: Record<string, string>;
+  bodyBase64: string;
+}
+
+interface RuntimeResponse {
+  ok: boolean;
+  status: number;
+  statusText: string;
+  headers: {
+    get(name: string): string | null;
+  };
+  text(): Promise<string>;
+  json<T>(): Promise<T>;
+  arrayBuffer(): Promise<ArrayBuffer>;
+  blob(): Promise<Blob>;
+}
+
+const textDecoder = new TextDecoder();
+
+const bytesToBase64 = (bytes: Uint8Array) => {
+  let binary = '';
+
+  for (let index = 0; index < bytes.length; index += 0x8000) {
+    const chunk = bytes.subarray(index, index + 0x8000);
+    binary += String.fromCharCode(...chunk);
+  }
+
+  return btoa(binary);
+};
+
+const base64ToBytes = (value: string) => {
+  if (!value) {
+    return new Uint8Array(0);
+  }
+
+  const binary = atob(value);
+  const bytes = new Uint8Array(binary.length);
+
+  for (let index = 0; index < binary.length; index += 1) {
+    bytes[index] = binary.charCodeAt(index);
+  }
+
+  return bytes;
+};
+
+const normalizeHeaders = (headers: Record<string, string>) => {
+  const normalized = new Map<string, string>();
+
+  for (const [key, value] of Object.entries(headers)) {
+    normalized.set(key.toLowerCase(), value);
+  }
+
+  return normalized;
+};
+
+const createRuntimeResponse = (response: ElectronHttpResponse): RuntimeResponse => {
+  const headers = normalizeHeaders(response.headers);
+  const bytes = base64ToBytes(response.bodyBase64);
+  const contentType = headers.get('content-type') || '';
+
+  return {
+    ok: response.ok,
+    status: response.status,
+    statusText: response.statusText,
+    headers: {
+      get(name: string) {
+        return headers.get(name.toLowerCase()) ?? null;
+      },
+    },
+    async text() {
+      return textDecoder.decode(bytes);
+    },
+    async json<T>() {
+      return JSON.parse(textDecoder.decode(bytes)) as T;
+    },
+    async arrayBuffer() {
+      return bytes.buffer.slice(
+        bytes.byteOffset,
+        bytes.byteOffset + bytes.byteLength,
+      ) as ArrayBuffer;
+    },
+    async blob() {
+      return new Blob([bytes], { type: contentType });
+    },
+  };
+};
+
+const headersToObject = (headers?: HeadersInit) => {
+  if (!headers) {
+    return {};
+  }
+
+  return Object.fromEntries(new Headers(headers).entries());
+};
+
+const serializeBody = async (body?: BodyInit | null) => {
+  if (body == null) {
+    return {};
+  }
+
+  if (typeof body === 'string') {
+    return { bodyText: body };
+  }
+
+  if (body instanceof ArrayBuffer) {
+    return { bodyBase64: bytesToBase64(new Uint8Array(body)) };
+  }
+
+  if (ArrayBuffer.isView(body)) {
+    return {
+      bodyBase64: bytesToBase64(
+        new Uint8Array(body.buffer, body.byteOffset, body.byteLength),
+      ),
+    };
+  }
+
+  if (body instanceof Blob) {
+    return {
+      bodyBase64: bytesToBase64(new Uint8Array(await body.arrayBuffer())),
+    };
+  }
+
+  throw new Error('Unsupported request body for Electron runtime.');
+};
+
+export const runtimeFetch = async (
+  url: string,
+  init: RequestInit = {},
+): Promise<Response | RuntimeResponse> => {
+  if (!window.electronDesktop?.httpRequest) {
+    return fetch(url, init);
+  }
+
+  const payload: ElectronHttpRequest = {
+    url,
+    method: init.method,
+    headers: headersToObject(init.headers),
+    ...(await serializeBody(init.body)),
+  };
+
+  const response = await window.electronDesktop.httpRequest(payload);
+  return createRuntimeResponse(response);
+};