Make Add Feedback button blue and shiny

Changes

Updated the "Add Feedback" button in the sidebar to have a blue gradient with a shiny glow effect:

• Applied a blue gradient (from-blue-500 via-blue-600 to-blue-700)
• Added hover state with darker blue gradient
• Added blue shadow/glow effect (shadow-blue-500/50) for the shiny appearance
• Smooth transition animation on hover