Sessions that ran Workflow-substrate pipelines read as near-zero
subagent spend: analyze_subagents() globs one level only, while
Workflow runs log under workflows/wf_*.json (per-agent summary) and
subagents/workflows/<runId>/agent-*.jsonl (raw usage). New
analyze_workflows() joins both — raw transcripts authoritative
(dedup by requestId, as everywhere), summary supplies stage labels
and models, label-prefix grouping (impl:3 -> impl), untracked
transcripts isolated under '?'. Report gains workflows[] and
workflow_totals; totals now include workflow spend.
Live check against a real 17-agent workflow run: raw 1.30M vs
reported 1.22M (the live counter's known ~7-11% under-tracking).
closes#28
