enhancement(ui): use consistent keycap styling for search keyboard shortcut

[arpan7sarkar]

Summary

The search input currently displays the Ctrl K keyboard shortcut as plain text, while other keyboard shortcuts in the application (such as Ask Assistant) are rendered using keycap-style UI elements. This creates an inconsistency in the interface.

Current Behavior

• The search input displays Ctrl K as plain text.
• Other keyboard shortcuts use keycap/button-style backgrounds.

Expected Behavior

Render the search keyboard shortcut using the same keycap styling as other shortcuts throughout the application to maintain a consistent visual language.

Why This Improvement?

• Improves visual consistency across the interface.
• Makes keyboard shortcuts easier to identify.
• Aligns with the existing design system and UX patterns.

[linear-code]

NAN-6116

[arpan7sarkar]

I'd be happy to work on this enhancement. If it looks good to the maintainers, could you please assign this issue to me? Thanks!
@mdp @nalanj @zaherg @dax