🎨 Palette: Add keyboard focus styles to back buttons

[dhaatrik]

💡 What: Added explicit keyboard focus styling (focus-visible:ring-2 focus-visible:ring-primary focus-visible:outline-none rounded-sm) to all navigation icon buttons (e.g., 'Go back' buttons) across multiple components.
🎯 Why: Because the application utilizes a brutalist design system with complex borders and shadow changes on hover, the default browser focus ring was often insufficient or overwritten, making it difficult for keyboard users to track their navigation focus state correctly.
📸 Before/After: See verify_focus.png in the earlier validation phase.
♿ Accessibility: This directly improves keyboard navigability by ensuring consistent and explicit visual feedback when the focus state is placed on back buttons.

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PR created automatically by Jules for task 493206173007864673 started by @DhaatuTheGamer

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