Promotes ADR-0009 from Proposed to Accepted after the grill-with-docs
session resolved all seven open questions. Bundles the SAP 10.3 and
RdSAP 10 specifications under docs/sap-spec/ plus a calculator design
sketch (module layout, monthly-loop pseudo-code, status table).
CONTEXT.md adds three new domain terms parallel to existing performance
language:
- Calculated SAP10 Performance (parallel to Effective / Lodged)
- SAP10 Calculation (process; implemented by Sap10Calculator)
- Measure Application (process; implemented by MeasureApplicator)
ML pipeline is NOT retired — it stays as the residual head once the
calculator reaches parity in Session B. ADR-0009 §"Grill outcomes" carries
the seven binding scope decisions plus three Session-A-scope changes
discovered during the grill (RdSAP §19 EER formula, SAP 10.2 Appendix A
cross-reference, RdSAP Table 29 cascade defaults).
