- visible_logs() called once per frame instead of 3+
- only render ListItems for visible window (~30-50) instead of all 10k
- visible_count() for scroll/enter checks without Vec allocation
- eps_history VecDeque: O(1) pop_front instead of O(n) Vec::remove(0)
- detect_level() zero-alloc case-insensitive byte compare
- colorize_entry() reduced string clones