refactor(pdf): simplify PDF module by removing redundant utilities

Remove helper functions (cmToPoints, inchesToPoints, mmToPoints,
createElement, PAGE_SIZES) and consolidate re-exports from
@react-pdf/renderer into a single export statement. Retain only
the getFilename utility and streamline the module to reduce
unnecessary abstraction over the underlying library.

src/core/pdf/index.js

@@ -1,121 +1,9 @@
-/**
- * PDF Generation Utilities
- * Wrapper around @react-pdf/renderer for PDF generation
- * 
- * Usage in modules:
- * import { renderToBuffer } from '@zen/core/pdf';
- */
-
-import { renderToBuffer as reactPdfRenderToBuffer } from '@react-pdf/renderer';
-import React from 'react';
+export { renderToBuffer, Document, Page, View, Text, Image, Link, StyleSheet, Font } from '@react-pdf/renderer';
 
 /**
- * Render a React PDF document to a buffer
- * @param {React.Element} document - React PDF document element
- * @returns {Promise<Buffer>} PDF buffer
- * 
- * @example
- * import { Document, Page, Text } from '@react-pdf/renderer';
- * 
- * const MyDoc = () => (
- *   <Document>
- *     <Page>
- *       <Text>Hello World</Text>
- *     </Page>
- *   </Document>
- * );
- * 
- * const buffer = await renderToBuffer(<MyDoc />);
- */
-export async function renderToBuffer(document) {
-  return await reactPdfRenderToBuffer(document);
-}
-
-/**
- * Create a React element for PDF rendering
- * @param {Function} Component - React component
- * @param {Object} props - Component props
- * @returns {React.Element}
- */
-export function createElement(Component, props) {
-  return React.createElement(Component, props);
-}
-
-/**
- * Get a suggested filename for a PDF
- * @param {string} prefix - Filename prefix
- * @param {string|number} identifier - Unique identifier
- * @param {Date} date - Date for the filename (default: today)
- * @returns {string} Suggested filename
- * 
- * @example
- * getFilename('invoice', '12345'); // 'invoice-12345-2024-01-15.pdf'
+ * Get a suggested filename for a PDF.
+ * @example getFilename('invoice', '12345') // 'invoice-12345-2024-01-15.pdf'
  */
 export function getFilename(prefix, identifier, date = new Date()) {
-  const dateStr = date.toISOString().split('T')[0];
-  return `${prefix}-${identifier}-${dateStr}.pdf`;
+  return `${prefix}-${identifier}-${date.toISOString().split('T')[0]}.pdf`;
 }
-
-/**
- * Convert centimeters to points (for PDF dimensions)
- * @param {number} cm - Centimeters
- * @returns {number} Points
- */
-export function cmToPoints(cm) {
-  return cm * 28.3465;
-}
-
-/**
- * Convert inches to points (for PDF dimensions)
- * @param {number} inches - Inches
- * @returns {number} Points
- */
-export function inchesToPoints(inches) {
-  return inches * 72;
-}
-
-/**
- * Convert millimeters to points (for PDF dimensions)
- * @param {number} mm - Millimeters
- * @returns {number} Points
- */
-export function mmToPoints(mm) {
-  return mm * 2.83465;
-}
-
-/**
- * Common page sizes in points
- */
-export const PAGE_SIZES = {
-  A4: { width: 595.28, height: 841.89 },
-  LETTER: { width: 612, height: 792 },
-  LEGAL: { width: 612, height: 1008 },
-  A3: { width: 841.89, height: 1190.55 },
-  A5: { width: 419.53, height: 595.28 },
-};
-
-// Re-export react-pdf components for convenience
-export { 
-  Document,
-  Page,
-  View,
-  Text,
-  Image,
-  Link,
-  StyleSheet,
-  Font,
-  PDFViewer,
-  BlobProvider,
-  PDFDownloadLink,
-} from '@react-pdf/renderer';
-
-// Default export
-export default {
-  renderToBuffer,
-  createElement,
-  getFilename,
-  cmToPoints,
-  inchesToPoints,
-  mmToPoints,
-  PAGE_SIZES,
-};