feat(design): add documentation guides and footer

[aizyohiy-hash]

Summary

This PR introduces the UI designs for key documentation guide pages and the global footer, enhancing the developer learning experience while providing consistent site-wide navigation and project resources.

Implemented

• Designed the Quickstart Docs page.
• Designed the SSR Guide Docs page.
• Designed the Error Handling Docs page.
• Designed the Footer section.

Goals

• Improve the developer onboarding journey with structured documentation.
• Provide dedicated guidance for common implementation scenarios.
• Ensure documentation is easy to navigate and visually consistent.
• Deliver a comprehensive footer with navigation, project resources, and community links.
• Maintain a responsive, accessible, and design-system-compliant user experience.

Type of Change

• UI/UX Design
• Bug Fix
• New Feature
• Breaking Change
• Documentation Update

Notes

These changes are focused on UI/UX design and do not introduce application logic or backend functionality.

Figma link here

https://www.figma.com/design/BSr242a615D8Lbg6WjT7l1/Use-stellar-design?node-id=0-1&p=f&t=ev4q750WePag3udj-0

Closes #128
Closes #130
Closes #132
Closes #132

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