Polish mobile responsive layout

[nikkkkj]

Fixes #833.
Also addresses the overlapping requirements in #824.

Summary

• Improve mobile nav sizing, touch targets, and hamburger menu accessibility
• Prevent hero terminal command overflow at narrow widths
• Stack hero CTAs cleanly on small screens and allow stats to wrap
• Improve bounty card mobile stacking for reward/meta/status rows
• Make footer columns and token address controls safer at mobile widths
• Add global overflow safeguards for media and small screens
• Restore missing frontend lib/animations and lib/utils helpers so existing imports resolve during production build

Verification

• npm run build

Notes

• Focused on the 375px/768px responsive issues named in the bounty: bounty cards, navigation hamburger, hero terminal readability, footer overflow, and horizontal scroll prevention.