Implement native print dialog for PDF export

- Replaced jsPDF client-side generation with Tauri's native print dialog
- Created PrintView component that renders note content in a print-optimized layout
- Added print-export window capability with webview creation and print permissions
- Implemented event-based communication between main window and print window
- Moved shared print/export utilities to printExport.ts (title extraction, filename sanitization)
- Changed export button icon from download

src/printExport.ts

@@ -0,0 +1,28 @@
+export interface PrintExportPayload {
+  fileName: string;
+  title: string;
+  html: string;
+  previewFont: string;
+  previewFontSize: number;
+}
+
+export const PRINT_EXPORT_QUERY_PARAM = 'printJob';
+const PRINT_EXPORT_STORAGE_PREFIX = 'print-export:';
+
+export const getPrintExportStorageKey = (jobId: string) =>
+  `${PRINT_EXPORT_STORAGE_PREFIX}${jobId}`;
+
+export const getNoteTitleFromContent = (content: string) => {
+  const firstLine = content
+    .split('\n')
+    .map((line) => line.trim())
+    .find((line) => line.length > 0);
+
+  return (firstLine || 'Untitled').replace(/^#+\s*/, '').trim();
+};
+
+export const sanitizeFileName = (name: string) =>
+  name
+    .replace(/[\\/:*?"<>|]/g, '-')
+    .replace(/\s+/g, ' ')
+    .trim() || 'note';