synthetic-bom expectations (manually calculated, synthetic)
A session JSON file begins with a UTF-8 BOM. Both detection and whole-file parsing remove the BOM and import normally.
Expectations
- detect=Supported; files[0].status=“complete”; one event, syn-msg-1.
- Summary: call_count=1, input_total_known=100, output_total_known=20, total_tokens_known=120; no diagnostics.