feat: add PNG, WebP, and PDF export options to customize generator page

[nishtha-agarwal-211]

Is your feature request related to a problem? Please describe.

Currently, users on the /customize page can only copy the SVG image URL or raw Markdown snippet. Many users want to download high-resolution raster images (PNG/WebP) or vector PDFs to use in resumes, portfolios, slide decks, or social media posts without taking manual screenshots.

Describe the solution you'd like

Add an "Export As" dropdown/action bar on the customizer page allowing users to download their monolith card in multiple formats:

1. PNG (High-resolution raster)
2. WebP (Optimized web format)
3. PDF (Vector document format)

Implementation details:

• Use client-side conversion tools (@resvg/resvg-js / html-to-image / jspdf) already in package.json.
• Trigger a toast notification (via sonner / react-hot-toast) on successful export.
• Retain exact theme colors, dimensions, and typography in exported files.

Describe alternatives you've considered

• Taking manual browser screenshots (results in variable resolution, cropped edges, and loss of transparent backgrounds).
• Server-side rendering (introduces extra server load and latency compared to fast client-side canvas/SVG conversion).

[nishtha-agarwal-211]

/claim

[github-actions]

🎉 Assigned! Welcome to the project, @nishtha-agarwal-211.

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