fix: header, sidebar UI and animations

[tsahimatsliah]

Summary

• Improve feed layout with full-width cards and reduced gaps
• Make header fixed instead of sticky for YouTube-like behavior
• Add hidden scrollbar that shows on hover
• Improve sidebar collapse animation with synchronized 300ms transitions
• Adjust sidebar padding and font sizes for consistency
• Make plus icon always visible in section headers

Test plan

• Verify feed cards are full-width with reduced gaps
• Verify header stays fixed on scroll (doesn't move up/down)
• Verify scrollbar is hidden by default and appears on hover
• Verify sidebar collapse/expand animation is smooth without glitches
• Verify sidebar padding and alignment is consistent in expanded and collapsed states

Preview domain

https://feed-layout-improvements.preview.app.daily.dev

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Project	Deployment	Actions	Updated (UTC)
daily-webapp	Error		Feb 2, 2026 10:24am

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
storybook	Ignored		Feb 2, 2026 10:24am

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