SGM-7012 - Update navigation menu and footer

[gitstart-app[bot]]

This PR was created by GitStart to address the requirements from this ticket: SGM-7012. This ticket was imported from: SGM-7012

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Description

1. Redesign the navigation menu and footer Figma specs here. and mockup here
2. Change the home page to light mode. https://www.figma.com/design/fudljjrGrUg5cDYTAo4Hra/Homepage?node-id=3851-43000&m=dev
3. Update the pages with purple mode with dark mode (Use good UI/UX judgement for now)

Test Plan

1. Ensure the navbar is as the figma both on desktop and mobile.
2. Ensure the footer is as the figma both on desktop and mobile.
3. Use excellent UI/UX judgement to ensure pages that were previously purple mode are rendering correctly.

Demo

https://www.loom.com/share/e84743573af440c09ab8ab7a6d92433a?sid=823e2808-de4b-4894-9d66-e6f3935337a9

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[gitstart-sourcegraph]

Thank you @traceyljohnson for the review. We're working on the updates

[gitstart-sourcegraph]

Focus ring shape is a bit odd, and we're using it inconsistently:

Hi @toolmantim , may you please clarify on this? Thank you.