Report research ROI in MAP diagnostics

[azalio]

Closes #202.

Summary:

• adds advisory research_roi to token_accounting.json
• shows per-agent costs and research ROI in /map-tokenreport
• adds research artifact/status/confidence/location summary to run_health_report.json
• documents the new diagnostics and updates schema/tests

Validation:

• pytest tests/test_map_step_runner.py::test_write_run_health_report_creates_report_and_manifest tests/test_map_step_runner.py::test_write_run_health_report_counts_direct_research_without_tokens tests/test_map_step_runner.py::test_write_run_health_report_includes_research_roi_and_warnings tests/test_map_step_runner.py::TestTokenAccounting::test_rebuild_adds_research_roi_summary tests/test_map_step_runner.py::TestTokenAccounting::test_token_report_shows_agent_costs_and_research_roi tests/test_artifact_schemas.py::test_validate_run_health_report_schema -v
• make check