feat(insights): give every category page a metric explainer + normalise keys to english

Two parts to the explainer surface, landed together because they share
the same i18n block and page props.

Coverage: every routed insights category page now passes an
`explainerMetric` prop, so the heading-side `?` glyph is present on all
37 pages instead of 13. The 24 newly covered metrics — body
composition (body water, bone/fat/muscle/lean mass, fat-free mass,
visceral fat), mobility (flights, walking distance/speed/steadiness,
asymmetry, double-support, step length, walking heart rate),
cardiovascular (pulse-wave velocity, vascular age), hearing
(environmental + headphone levels, loud-sound events), respiratory
rate, daylight, blood glucose, and skin temperature — each gain a one
to two sentence layperson definition grounded in standard clinical
references, shipped in all six locales.

Keys: the explainer key segments were a German/English mix
(`blutdruck`, `puls`, `gewicht`, `schlaf`, `stimmung`, `medikamente`
alongside English ones). Rename them to English to match the
naming-convention ADR — `bloodPressure`, `pulse`, `weight`, `sleep`,
`mood`, `medications` — across every locale, and update the
`explainerMetric` prop values that reference them. These are i18n key
segments, not route slugs, so the slug contract is untouched.

src/app/insights/audio-events/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsLaermereignissePage() {
       insightMetric="AUDIO_EXPOSURE_EVENT"
       chartKey="audioExposureEvent"
       i18nPrefix="insights.audioExposureEvent"
+      explainerMetric="audioEvents"
       color="#ff79c6"
       unit=""
       yAxisUnit=""

src/app/insights/blood-glucose/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsBlutzuckerPage() {
       insightMetric="BLOOD_GLUCOSE"
       chartKey="bloodGlucose"
       i18nPrefix="insights.bloodGlucose"
+      explainerMetric="bloodGlucose"
       color="#ff79c6"
       unit="mg/dL"
       yAxisUnit="mg/dL"

src/app/insights/blood-pressure/page.tsx

@@ -52,7 +52,7 @@ export default function InsightsBlutdruckPage() {
       <SubPageShell
         title={t("insights.bloodPressureSectionTitle")}
         description={t("insights.subPage.blutdruckDescription")}
-        explainerMetric="blutdruck"
+        explainerMetric="bloodPressure"
       >
         <MetricEmptyState
           icon={<HeartPulse className="size-6" />}
@@ -100,7 +100,7 @@ export default function InsightsBlutdruckPage() {
     <SubPageShell
       title={t("insights.bloodPressureSectionTitle")}
       description={t("insights.subPage.blutdruckDescription")}
-      explainerMetric="blutdruck"
+      explainerMetric="bloodPressure"
     >
       <HealthChartDynamic
         chartKey="bp"

src/app/insights/body-water/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsKoerperwasserPage() {
       insightMetric="TOTAL_BODY_WATER"
       chartKey="totalBodyWater"
       i18nPrefix="insights.totalBodyWater"
+      explainerMetric="bodyWater"
       color="#8be9fd"
       unit="kg"
       yAxisUnit="kg"

src/app/insights/bone-mass/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsKnochenmassePage() {
       insightMetric="BONE_MASS"
       chartKey="boneMass"
       i18nPrefix="insights.boneMass"
+      explainerMetric="boneMass"
       color="#ffb86c"
       unit="kg"
       yAxisUnit="kg"

src/app/insights/daylight/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsTageslichtPage() {
       insightMetric="TIME_IN_DAYLIGHT"
       chartKey="timeInDaylight"
       i18nPrefix="insights.timeInDaylight"
+      explainerMetric="daylight"
       color="#50fa7b"
       unit="min"
       yAxisUnit="min"

src/app/insights/double-support-time/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsDoppelstandphasePage() {
       insightMetric="WALKING_DOUBLE_SUPPORT"
       chartKey="walkingDoubleSupport"
       i18nPrefix="insights.walkingDoubleSupport"
+      explainerMetric="doubleSupportTime"
       color="#50fa7b"
       unit="%"
       yAxisUnit="%"

src/app/insights/environmental-audio/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsLaermbelastungPage() {
       insightMetric="AUDIO_EXPOSURE_ENV"
       chartKey="audioExposureEnv"
       i18nPrefix="insights.audioExposureEnv"
+      explainerMetric="environmentalAudio"
       color="#ff79c6"
       unit="dBA"
       yAxisUnit="dBA"

src/app/insights/fat-free-mass/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsFettfreieMassePage() {
       insightMetric="FAT_FREE_MASS"
       chartKey="fatFreeMass"
       i18nPrefix="insights.fatFreeMass"
+      explainerMetric="fatFreeMass"
       color="#bd93f9"
       unit="kg"
       yAxisUnit="kg"

src/app/insights/fat-mass/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsFettmassePage() {
       insightMetric="FAT_MASS"
       chartKey="fatMass"
       i18nPrefix="insights.fatMass"
+      explainerMetric="fatMass"
       color="#ffb86c"
       unit="kg"
       yAxisUnit="kg"

src/app/insights/flights-climbed/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsStockwerkePage() {
       insightMetric="FLIGHTS_CLIMBED"
       chartKey="flightsClimbed"
       i18nPrefix="insights.flightsClimbed"
+      explainerMetric="flightsClimbed"
       color="#50fa7b"
       unit="flights"
       yAxisUnit="flights"

src/app/insights/headphone-audio/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsKopfhoererpegelPage() {
       insightMetric="AUDIO_EXPOSURE_HEADPHONE"
       chartKey="audioExposureHeadphone"
       i18nPrefix="insights.audioExposureHeadphone"
+      explainerMetric="headphoneAudio"
       color="#ff79c6"
       unit="dBA"
       yAxisUnit="dBA"

src/app/insights/lean-body-mass/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsMagermassePage() {
       insightMetric="LEAN_BODY_MASS"
       chartKey="leanBodyMass"
       i18nPrefix="insights.leanBodyMass"
+      explainerMetric="leanBodyMass"
       color="#bd93f9"
       unit="kg"
       yAxisUnit="kg"

src/app/insights/medications/page.tsx

@@ -114,7 +114,7 @@ export default function InsightsMedikamentePage() {
     return (
       <SubPageShell
         title={t("insights.medicationCompliance")}
-        explainerMetric="medikamente"
+        explainerMetric="medications"
       >
         <div className="flex items-center justify-center py-12">
           <Loader2 className="text-primary h-6 w-6 animate-spin motion-reduce:animate-none" />
@@ -130,7 +130,7 @@ export default function InsightsMedikamentePage() {
     return (
       <SubPageShell
         title={t("insights.medicationCompliance")}
-        explainerMetric="medikamente"
+        explainerMetric="medications"
       >
         <EmptyState
           icon={<Pill className="size-6" />}
@@ -156,7 +156,7 @@ export default function InsightsMedikamentePage() {
     <SubPageShell
       title={t("insights.medicationCompliance")}
       description={t("insights.subPage.medikamenteDescription")}
-      explainerMetric="medikamente"
+      explainerMetric="medications"
     >
       <div
         className={

src/app/insights/mood/page.tsx

@@ -76,7 +76,7 @@ export default function InsightsStimmungPage() {
       <SubPageShell
         title={t("insights.moodSectionTitle")}
         description={t("insights.subPage.stimmungDescription")}
-        explainerMetric="stimmung"
+        explainerMetric="mood"
       >
         <MetricEmptyState
           icon={<Smile className="size-6" />}
@@ -97,7 +97,7 @@ export default function InsightsStimmungPage() {
     <SubPageShell
       title={t("insights.moodSectionTitle")}
       description={t("insights.subPage.stimmungDescription")}
-      explainerMetric="stimmung"
+      explainerMetric="mood"
     >
       <MoodChart
         chartKey="mood"

src/app/insights/muscle-mass/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsMuskelmassePage() {
       insightMetric="MUSCLE_MASS"
       chartKey="muscleMass"
       i18nPrefix="insights.muscleMass"
+      explainerMetric="muscleMass"
       color="#bd93f9"
       unit="kg"
       yAxisUnit="kg"

src/app/insights/pulse-wave-velocity/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsPulswellengeschwindigkeitPage() {
       insightMetric="PULSE_WAVE_VELOCITY"
       chartKey="pulseWaveVelocity"
       i18nPrefix="insights.pulseWaveVelocity"
+      explainerMetric="pulseWaveVelocity"
       color="#ff5555"
       unit="m/s"
       yAxisUnit="m/s"

src/app/insights/pulse/page.tsx

@@ -62,7 +62,7 @@ export default function InsightsPulsPage() {
       <SubPageShell
         title={t("insights.pulseSectionTitle")}
         description={t("insights.subPage.pulsDescription")}
-        explainerMetric="puls"
+        explainerMetric="pulse"
       >
         <MetricEmptyState
           icon={<Heart className="size-6" />}
@@ -113,7 +113,7 @@ export default function InsightsPulsPage() {
     <SubPageShell
       title={t("insights.pulseSectionTitle")}
       description={t("insights.subPage.pulsDescription")}
-      explainerMetric="puls"
+      explainerMetric="pulse"
     >
       <HealthChartDynamic
         chartKey="pulse"

src/app/insights/respiratory-rate/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsAtemfrequenzPage() {
       insightMetric="RESPIRATORY_RATE"
       chartKey="respiratoryRate"
       i18nPrefix="insights.respiratoryRate"
+      explainerMetric="respiratoryRate"
       color="#8be9fd"
       unit="breaths/min"
       yAxisUnit="breaths/min"

src/app/insights/skin-temperature/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsHauttemperaturPage() {
       insightMetric="SKIN_TEMPERATURE"
       chartKey="skinTemperature"
       i18nPrefix="insights.skinTemperature"
+      explainerMetric="skinTemperature"
       color="#ffb86c"
       unit="°C"
       yAxisUnit="°C"

src/app/insights/sleep/page.tsx

@@ -38,7 +38,7 @@ export default function InsightsSchlafPage() {
       <SubPageShell
         title={t("insights.sleep.title")}
         description={t("insights.sleep.description")}
-        explainerMetric="schlaf"
+        explainerMetric="sleep"
       >
         <MetricEmptyState
           icon={<Moon className="size-6" />}
@@ -61,7 +61,7 @@ export default function InsightsSchlafPage() {
     <SubPageShell
       title={t("insights.sleep.title")}
       description={t("insights.sleep.description")}
-      explainerMetric="schlaf"
+      explainerMetric="sleep"
     >
       <SleepOverview />
 

src/app/insights/step-length/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsSchrittlaengePage() {
       insightMetric="WALKING_STEP_LENGTH"
       chartKey="walkingStepLength"
       i18nPrefix="insights.walkingStepLength"
+      explainerMetric="stepLength"
       color="#50fa7b"
       unit="m"
       yAxisUnit="m"

src/app/insights/vascular-age/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsGefaessalterPage() {
       insightMetric="VASCULAR_AGE"
       chartKey="vascularAge"
       i18nPrefix="insights.vascularAge"
+      explainerMetric="vascularAge"
       color="#ff79c6"
       unit="years"
       yAxisUnit="years"

src/app/insights/visceral-fat/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsViszeralfettPage() {
       insightMetric="VISCERAL_FAT"
       chartKey="visceralFat"
       i18nPrefix="insights.visceralFat"
+      explainerMetric="visceralFat"
       color="#ffb86c"
       unit=""
       yAxisUnit=""

src/app/insights/walking-asymmetry/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsGangasymmetriePage() {
       insightMetric="WALKING_ASYMMETRY"
       chartKey="walkingAsymmetry"
       i18nPrefix="insights.walkingAsymmetry"
+      explainerMetric="walkingAsymmetry"
       color="#50fa7b"
       unit="%"
       yAxisUnit="%"

src/app/insights/walking-distance/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsGehstreckePage() {
       insightMetric="WALKING_RUNNING_DISTANCE"
       chartKey="walkingRunningDistance"
       i18nPrefix="insights.walkingRunningDistance"
+      explainerMetric="walkingDistance"
       color="#50fa7b"
       unit="km"
       yAxisUnit="km"

src/app/insights/walking-heart-rate/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsGehpulsPage() {
       insightMetric="WALKING_HEART_RATE_AVERAGE"
       chartKey="walkingHeartRateAverage"
       i18nPrefix="insights.walkingHeartRateAverage"
+      explainerMetric="walkingHeartRate"
       color="#ff5555"
       unit="bpm"
       yAxisUnit="bpm"

src/app/insights/walking-speed/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsGehgeschwindigkeitPage() {
       insightMetric="WALKING_SPEED"
       chartKey="walkingSpeed"
       i18nPrefix="insights.walkingSpeed"
+      explainerMetric="walkingSpeed"
       color="#50fa7b"
       unit="km/h"
       yAxisUnit="km/h"

src/app/insights/walking-steadiness/page.tsx

@@ -19,6 +19,7 @@ export default function InsightsGangstabilitaetPage() {
       insightMetric="WALKING_STEADINESS"
       chartKey="walkingSteadiness"
       i18nPrefix="insights.walkingSteadiness"
+      explainerMetric="walkingSteadiness"
       color="#50fa7b"
       unit="%"
       yAxisUnit="%"

src/app/insights/weight/page.tsx

@@ -44,7 +44,7 @@ export default function InsightsGewichtPage() {
       <SubPageShell
         title={t("insights.weightSectionTitle")}
         description={t("insights.subPage.gewichtDescription")}
-        explainerMetric="gewicht"
+        explainerMetric="weight"
       >
         <MetricEmptyState
           icon={<Scale className="size-6" />}
@@ -74,7 +74,7 @@ export default function InsightsGewichtPage() {
     <SubPageShell
       title={t("insights.weightSectionTitle")}
       description={t("insights.subPage.gewichtDescription")}
-      explainerMetric="gewicht"
+      explainerMetric="weight"
     >
       <HealthChartDynamic
         chartKey="weight"

src/components/insights/__tests__/metric-explainer.test.tsx

@@ -41,25 +41,52 @@ function KeyProbe({ metric }: { metric: string }) {
   );
 }
 
+// v1.8.0 — English key segments (ADR-0001). Every routed insights
+// category page now passes one of these; the explainer copy ships in
+// all six locales.
 const METRICS = [
-  "blutdruck",
-  "puls",
-  "gewicht",
+  "bloodPressure",
+  "pulse",
+  "weight",
   "bmi",
-  "schlaf",
-  "stimmung",
-  "medikamente",
+  "sleep",
+  "mood",
+  "medications",
   "restingHr",
   "hrv",
   "oxygenSaturation",
   "bodyTemperature",
   "activeEnergy",
   "workouts",
+  "respiratoryRate",
+  "bodyWater",
+  "boneMass",
+  "fatFreeMass",
+  "fatMass",
+  "muscleMass",
+  "visceralFat",
+  "leanBodyMass",
+  "flightsClimbed",
+  "walkingDistance",
+  "walkingSteadiness",
+  "walkingHeartRate",
+  "walkingAsymmetry",
+  "doubleSupportTime",
+  "stepLength",
+  "walkingSpeed",
+  "pulseWaveVelocity",
+  "vascularAge",
+  "environmentalAudio",
+  "headphoneAudio",
+  "audioEvents",
+  "daylight",
+  "bloodGlucose",
+  "skinTemperature",
 ] as const;
 
 describe("<MetricExplainer>", () => {
   it("renders an icon-only trigger button with a metric-specific accessible label (EN)", () => {
-    const html = ssr(<MetricExplainer metric="blutdruck" />);
+    const html = ssr(<MetricExplainer metric="bloodPressure" />);
     const trigger = html.match(
       /<button[^>]*data-slot="metric-explainer-trigger"[^>]*>/,
     );
@@ -72,7 +99,7 @@ describe("<MetricExplainer>", () => {
     // `min-h-11 min-w-11`; the surrounding heading row keeps its stride
     // because `-my-3 -mx-2` swallows the extra reach. Pinned so a future
     // refactor can't collapse the hit surface back to the visual chip.
-    const html = ssr(<MetricExplainer metric="puls" />);
+    const html = ssr(<MetricExplainer metric="pulse" />);
     const trigger = html.match(
       /<button[^>]*data-slot="metric-explainer-trigger"[^>]*>/,
     );
@@ -94,13 +121,13 @@ describe("<MetricExplainer>", () => {
     // the user activates the trigger. Pinning the negative keeps a
     // future "open on render" refactor from leaking copy into the
     // static markup.
-    const html = ssr(<MetricExplainer metric="gewicht" />);
+    const html = ssr(<MetricExplainer metric="weight" />);
     expect(html).not.toContain('data-slot="metric-explainer-body"');
     expect(html).not.toContain('data-slot="metric-explainer-title"');
   });
 
   it("localises the trigger label in German", () => {
-    const html = ssr(<MetricExplainer metric="schlaf" />, "de");
+    const html = ssr(<MetricExplainer metric="sleep" />, "de");
     const trigger = html.match(
       /<button[^>]*data-slot="metric-explainer-trigger"[^>]*>/,
     );