feat(figma): design dark mode pricing and checkout flows

[aizyohiy-hash]

Summary

Designed the Dark Mode UI/UX for StellarProof's pricing and checkout experiences in Figma, covering both Web3 XLM payments and Web2 fiat payments while maintaining consistency with the platform's existing design system.

What Was Done

• Created high-fidelity Dark Mode designs for the pricing and checkout experiences.
• Designed pricing tier cards for Free, Personal, Business, and Enterprise plans.
• Designed a detailed pricing comparison table for comparing plan features.
• Designed the XLM checkout flow for approving payments through Freighter.
• Designed the fiat checkout flow for credit card payments and subscription purchases.
• Applied consistent Dark Mode surfaces, typography, spacing, alignment, and contrast.
• Used reusable Figma components and auto-layout for maintainable designs.
• Created responsive layouts and variants where appropriate.
• Organized frames, layers, and components with clear naming and structure.
• Ensured a cohesive user experience across pricing selection and payment flows.

Scope

This PR contains Figma/UI/UX design work only and does not include frontend implementation.

Related Issues

Closes #573
Closes #574
Closes #575
Closes #576

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@aizyohiy-hash Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

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[Tybravo]

@aizyohiy-hash Good work done. I appreciate your contribution