feat(labs): add the Laborwerte page, navigation, and OpenAPI contract

A dedicated /labs page hosts manual entry and a per-analyte view: the
four essentials (biomarker, value, unit, date) stay visible, the
reference range, panel grouping and note sit under an optional section.
Results group by analyte with a small inline trend once an analyte has
two or more readings. The reference-range badge is deliberately neutral
and calm — an out-of-range value reads as a quiet directional marker, not
an alarming red.

Adds the labs section toggle to the health-record export panel, the /labs
nav entries, the /api/labs OpenAPI routes, and the labs copy across all
six locales.

src/components/settings/health-record-export-panel.tsx

@@ -56,6 +56,7 @@ interface SectionState {
   compliance: boolean;
   mood: boolean;
   bmi: boolean;
+  labs: boolean;
 }
 
 const DEFAULT_SECTIONS: SectionState = {
@@ -76,6 +77,7 @@ const DEFAULT_SECTIONS: SectionState = {
   compliance: true,
   mood: false, // privacy default
   bmi: true,
+  labs: true,
 };
 
 function buildSelectionSections(s: SectionState) {
@@ -102,6 +104,7 @@ function buildSelectionSections(s: SectionState) {
     medications: { list: s.medList, compliance: s.compliance },
     mood: s.mood,
     bmi: s.bmi,
+    labs: s.labs,
   };
 }
 
@@ -411,6 +414,11 @@ export function HealthRecordExportPanel() {
                   checked={sections.mood}
                   onToggle={() => toggle("mood")}
                 />
+                <ToggleRow
+                  label={t("settings.healthRecord.labs")}
+                  checked={sections.labs}
+                  onToggle={() => toggle("labs")}
+                />
               </div>
 
               {isPdfLike && (