Add indexed_work_elapsed_ms and unlogged_overhead_ms to the incremental speed benchmark output while preserving the existing elapsed_ms and logged_elapsed_ms fields. This separates cold CLI wall time from the logged indexing path so future speedup work can target the correct latency term.
Validation: python3 -m py_compile scripts/benchmark-incremental-speed.py; git diff --check; scripts/benchmark-incremental-speed.py --files 20 --functions-per-file 4 --changed-files 1 --min-speedup 0.5 --timeout 120 --out /private/tmp/cbm-incr-speed-overhead-fields-smoke-pass.json
Signed-off-by: Andrew Hundt <ATHundt@gmail.com>