fix(#92): search results appear in viewport without scrolling

Problem: After searching, results appeared below the fold requiring users to scroll.
This created confusion and potential drop-off.

Solution: Implemented two-state layout
- Hero mode: Full landing page with marketing sections
- Results mode: Compact search bar + results immediately visible

UX Improvements:
- Results now appear IN viewport (no scrolling needed)
- Sticky compact search bar for easy re-searching
- 'New Search' button to return to hero
- Staggered result card animations (75ms delay) for premium feel
- Results header shows 'Searching...' during loading (not stale data)

Technical Changes:
- Extracted CompactSearchBar component
- Extracted ResultCard component with animation
- Added currentRepoId/isCustomRepo state for search context
- Removed scrollToResults() hack
- Fixed loading state showing old results count

Author: DevanshuNEU