feat: add PDF export for memos using browser print API

[Faizaanp]

Add PDF Export for Memos

Fixes #5449

Overview

Implements a PDF export feature for individual memos using the browser's native print API. This approach provides zero-bundle-size increase, perfect rendering fidelity, and native browser print/save-as-PDF functionality.

Changes Made

Frontend Components

• MemoActionMenu: Added "Export as PDF" menu item in the Copy submenu with FileDownIcon
• MemoActionMenu hooks: Added handleExportAsPDF callback with error handling
• MemoView: Added data-memo-name attribute for DOM targeting

Core Functionality

• web/src/utils/print.ts: New utility that:
  • Opens a new window with the memo content
  • Applies print-specific styles
  • Triggers the browser print dialog
  • Automatically closes after print/cancel/save

Technical Details

Implementation Approach:

• Uses browser-native window.print() API
• No external dependencies (no jsPDF, no html2canvas)
• Respects browser's native print dialog and PDF settings
• Memo content cloned into new window for isolated printing

###screenshots