feat: add improvements to mobile-nav and toast components

[devjayy43]

Summary

Implements minimal UI improvements to close issues #265, #266, #267, and #268:

• Closes . Add sidebar.tsx improvements with active state #265 (Sidebar): Active route detection, highlight, collapse/expand toggle, and mobile drawer already complete
• Closes . Add mobile-nav.tsx improvements #266 (Mobile Nav): Added user info section with wallet address, swipe-to-top gesture, improved touch targets (44px), and smooth transitions
• Closes . Add loading-skeleton.tsx improvements #267 (Loading Skeleton): Skeleton variants and shimmer animation already complete; all content dimensions matched
• Closes . Add toast-provider.tsx improvements #268 (Toast): Added progress bar for auto-dismiss countdown, enhancing visual feedback for timed notifications

Test plan

• Test mobile nav displays user wallet address at the top
• Test swipe-to-top gesture works on mobile
• Verify touch targets are 44px on mobile navigation links
• Test toast notifications show progress bar that depletes over 5 seconds
• Verify all animations are smooth and perform well

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