fix unbounded video cache

• Fixes training hangs at iteration 700-800 caused by file handle exhaustion from unbounded decoder cache growth
• Adds LRU eviction with max size (default 50) to limit open file handles per process
• minimum throughput impact.

Fix Aggregate

Merge the fix from LeRobot official repo for fixing dataset aggregation functionality.

Relevant PR: huggingface#2550

remove unused large files

v0.4.1-genesis-20241121

remove big files in artifact folder