feat(feed): rewrite feed page with full HeroUI/Tailwind polish + fix API client

- Complete feed page rewrite: HeroUI cards, framer-motion stagger/AnimatePresence,
  inline SVG icons, tabbed feed/trending/bookmarks, optimistic like/bookmark,
  per-post comment panels, character counter, copy-link with CheckIcon feedback,
  SkeletonCard loading state, EmptyState per tab
- Fix api.ts: add unbookmarkPost (DELETE /api/feed/{id}/bookmark),
  add params to getTrendingPosts (hours, limit) and getBookmarkedPosts (page, limit),
  ensure all calls use api.METHOD() pattern with normalised response shapes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jasperfordesq-ai