fix(targets): no adult weight and BMI bands on a child's record

Now that the BMI chart draws inside a managed record, a child's normal
BMI sat in the red under-17 band, and the weight page painted the adult
WHO band (about 26 to 35 kg for 118 cm), so a healthy 21 kg read as
underweight. The release's own weight-band test pinned that band.

No band here knows a child's age yet. For a record under 18, or a
managed record with no date of birth, the targets read names no WHO
weight range, no BMI range and no category; the record's own weight
target still shows, and the values and the chart stay. The BMI chart
and the weight band draw only what the server names. The weight-band
test now uses an adult height and gains the child case.

The targets builder and the vitals builder grow by two lines each for
the flag; their size baselines are raised to match.

src/lib/targets/__tests__/builders.test.ts

@@ -274,3 +274,50 @@ describe("buildVitalTargets — user weight target", () => {
     expect(weight?.source).toBe("Custom");
   });
 });
+
+describe("buildVitalTargets — a child's record", () => {
+  // 118 cm and 21 kg: a BMI of about 15, normal for a six-year-old and red
+  // under the adult cut-offs.
+  const child = {
+    recentMeasurements: [],
+    restingPulseProxy: [],
+    latestByType: { WEIGHT: 21 },
+    average30ByType: { WEIGHT: 21 },
+    heightCm: 118,
+    age: 6,
+    gender: null,
+    timezone: TZ,
+    now: NOW,
+    weightTargetOverride: null,
+    adultBands: false,
+  };
+  const card = (
+    targets: ReturnType<typeof buildVitalTargets>["targets"],
+    type: string,
+  ) => targets.find((t) => t.type === type);
+
+  it("keeps the values and names no adult band or category", () => {
+    const { targets } = buildVitalTargets(child);
+    expect(card(targets, "WEIGHT")).toMatchObject({
+      current: 21,
+      range: null,
+      classification: null,
+    });
+    expect(card(targets, "BMI")).toMatchObject({
+      current: 15.1,
+      range: null,
+      classification: null,
+    });
+  });
+
+  it("keeps the record's own weight target", () => {
+    const { targets } = buildVitalTargets({
+      ...child,
+      weightTargetOverride: { min: 19, max: 24 },
+    });
+    expect(card(targets, "WEIGHT")).toMatchObject({
+      range: { min: 19, max: 24 },
+      source: "Custom",
+    });
+  });
+});

src/lib/targets/build-response.ts

@@ -116,6 +116,7 @@ export async function buildTargetsResponse(user: AuthedUser) {
         select: {
           heightCm: true,
           dateOfBirth: true,
+          managedProfileAt: true,
           gender: true,
           glucoseUnit: true,
           hasDiabetes: true,
@@ -274,6 +275,7 @@ export async function buildTargetsResponse(user: AuthedUser) {
     average30ByType,
     heightCm,
     age,
+    adultBands: age != null ? age >= 18 : dbUser?.managedProfileAt == null,
     gender,
     timezone,
     now,

src/lib/targets/vitals-builder.ts

@@ -74,6 +74,13 @@ interface VitalTargetsInput {
    * names a category, not a goal. Absent or `null` keeps the age band.
    */
   bpTargetOverride?: BloodPressureTargetRange | null;
+  /**
+   * Whether the adult WHO weight and BMI cut-offs apply. No band here knows a
+   * child's age yet, so for a record under 18, or a managed one with no date
+   * of birth, the weight card keeps only the record's own target, the BMI
+   * card names no band, and neither names a category. Absent means they do.
+   */
+  adultBands?: boolean;
 }
 
 export interface VitalTargetsResult {
@@ -170,6 +177,7 @@ export function buildVitalTargets({
   now,
   weightTargetOverride,
   bpTargetOverride = null,
+  adultBands = true,
 }: VitalTargetsInput): VitalTargetsResult {
   const targets: TargetItem[] = [];
   const consistencyClock = { timezone, now };
@@ -181,10 +189,11 @@ export function buildVitalTargets({
   // v1.34 — a user-set target outranks the WHO BMI band. The BMI
   // classification below stays WHO-derived either way: it names which BMI
   // category a reading falls in, which is a reference fact and not a goal.
+  const whoHeightCm = adultBands ? heightCm : null;
   const weightRange =
-    weightTargetOverride ?? (heightCm ? getWeightRange(heightCm) : null);
+    weightTargetOverride ?? (whoHeightCm ? getWeightRange(whoHeightCm) : null);
   let weightClassification: TargetItem["classification"] = null;
-  if (latestByType.WEIGHT != null && heightCm) {
+  if (latestByType.WEIGHT != null && whoHeightCm) {
     const heightM = heightCm / 100;
     const classification = classifyBMI(
       latestByType.WEIGHT / (heightM * heightM),
@@ -389,14 +398,14 @@ export function buildVitalTargets({
         ? Math.round((averageWeight / heightSquared) * 10) / 10
         : null;
     let bmiClassification: TargetItem["classification"] = null;
-    if (currentBmi != null) {
+    if (currentBmi != null && adultBands) {
       const classification = classifyBMI(currentBmi);
       bmiClassification = {
         category: classification.category,
         color: classification.color,
       };
     }
-    const bmiRange = { min: 18.5, max: 24.9 };
+    const bmiRange = adultBands ? { min: 18.5, max: 24.9 } : null;
     targets.push({
       type: "BMI",
       label: "BMI",