Function diff_tool_calls 

pub fn diff_tool_calls(
    run_id_a: &str,
    events_a: &[RunEvent],
    run_id_b: &str,
    events_b: &[RunEvent],
) -> DiffSummary

Diff the tool-call sequences of two runs.

Algorithm

1. Extract tool calls (kind=“tool_called”) from both event sequences
2. Compute LCS alignment on tool names
3. For each index:
   • Not in LCS → Added or Removed
   • In LCS with seq mismatch → Reordered
   • In LCS with payload difference → ParamDelta

Returns a DiffSummary with all changes and an identical flag.