Remove illustrative figures from category sub-pages

Update DeepSeek logo, tooltip format, and category names

Remove Test Set/Validation Set tabs, keep single results view

Update category structure to OpenHands Index with 5 categories

Replace all AstaBench references with OpenHands Index

Revert homepage simplification - keep original design

Optimize app loading: simplify home page to avoid expensive data loading at startup

Initial OpenHands Index leaderboard based on ASTA Bench