Show estimated HbA1c in mmol/mol (IFCC) alongside the % value

Dutch lab results conventionally report HbA1c in mmol/mol rather than
DCCT/NGSP %. Adds gmi_mmol_per_mol() using the standard IFCC conversion
(Hoelzel et al. 2004) and shows it next to the existing % value on the
Samenvatting page and in the PDF summary.

Closes gitea #25.

pdf_export.py

@@ -28,6 +28,7 @@ from reporting import (
     agp_percentile_bands,
     completeness_warning,
     detect_events,
+    gmi_mmol_per_mol,
     gmi_percent,
     percent_cv,
     sensor_active_percent,
@@ -178,7 +179,8 @@ def _add_summary_section(pdf: FPDF, glucose: pd.DataFrame, start, end) -> None:
     pdf.set_font("Helvetica", "", 11)
     pdf.cell(0, 6, f"Sensordekking: {active_pct:.0f}%", **_LINE_KWARGS)
     pdf.cell(0, 6, f"Gemiddelde glucose: {mean_mmol:.1f} mmol/L", **_LINE_KWARGS)
-    pdf.cell(0, 6, f"Geschat HbA1c (GMI): {gmi_percent(mean_mmol):.1f}%", **_LINE_KWARGS)
+    gmi = gmi_percent(mean_mmol)
+    pdf.cell(0, 6, f"Geschat HbA1c (GMI): {gmi:.1f}% ({gmi_mmol_per_mol(gmi):.0f} mmol/mol)", **_LINE_KWARGS)
     pdf.cell(0, 6, f"Variabiliteit (%CV): {percent_cv(glucose):.0f}%", **_LINE_KWARGS)
     pdf.ln(2)
     pdf.cell(0, 6, f"Zeer laag (<3.0 mmol/L): {tir['very_low']:.0f}%", **_LINE_KWARGS)