Add working PDF download button for scan results

[ieliofficial]

The CSS class .landing-download-pdf exists in LandingPage.css but no button is rendered in the JSX. The handleDownloadPdf function exists but only shows an alert.

Requirements:

1. Add a "Download PDF" button that appears when scan results are available (when hasResults is true)
2. Integrate a PDF library (jspdf recommended for simplicity)
3. Generate a PDF containing:
   • Summary of each problem category
   • List of problems found
   • "What's Good" section
4. Button should be placed near the subtitle after scan completes

Options

• Option A: Simple text-based PDF (faster to implement)
• Option B: HTML-to-PDF using html2pdf.js (more complete but larger dependency)

[ieliofficial]

@DevOlabode I've updated this issue for better clarity. Let me know if you have questions.