fix(ui): introduce FieldGroup and unify the add-form rhythm

The measurement add form opened with a horizontal type row (label beside
the select) while every field below it stacked label-above-control, so
the form read with two competing rhythms. Introduce a small FieldGroup
primitive — the long-standing space-y-2 label-above-control idiom in one
place — and route the measurement, mood and baseline forms through it so
they share one vertical rhythm. The type row now stacks like the rest.

Output stays byte-identical for the already-vertical groups; only the
type row changes, by design.

src/components/measurements/measurement-form.tsx

@@ -12,6 +12,7 @@ import {
 } from "@/components/ui/dropdown-menu";
 import { Input } from "@/components/ui/input";
 import { DateTimeField } from "@/components/ui/date-time-field";
+import { FieldGroup } from "@/components/ui/field-group";
 import { Label } from "@/components/ui/label";
 import {
   Select,
@@ -386,12 +387,9 @@ export function MeasurementForm({
 
   return (
     <form id={formId} onSubmit={handleSubmit} className="space-y-4">
-      <div className="flex items-center gap-3">
-        <Label htmlFor="measurement-type" className="shrink-0">
-          {t("measurements.type")}
-        </Label>
+      <FieldGroup htmlFor="measurement-type" label={t("measurements.type")}>
         <Select value={type} onValueChange={setType}>
-          <SelectTrigger id="measurement-type" className="flex-1">
+          <SelectTrigger id="measurement-type" className="w-full">
             <SelectValue />
           </SelectTrigger>
           <SelectContent>
@@ -402,7 +400,7 @@ export function MeasurementForm({
             ))}
           </SelectContent>
         </Select>
-      </div>
+      </FieldGroup>
 
       {isBpMode ? (
         <div className="grid gap-4 sm:grid-cols-3">
@@ -463,16 +461,16 @@ export function MeasurementForm({
           </div>
         </div>
       ) : (
-        <div className="space-y-2">
-          <Label htmlFor="value">
-            {t("measurements.valueWithUnit", {
-              unit: typeInfo
-                ? "unitKey" in typeInfo
-                  ? t(typeInfo.unitKey)
-                  : typeInfo.unit
-                : "",
-            })}
-          </Label>
+        <FieldGroup
+          htmlFor="value"
+          label={t("measurements.valueWithUnit", {
+            unit: typeInfo
+              ? "unitKey" in typeInfo
+                ? t(typeInfo.unitKey)
+                : typeInfo.unit
+              : "",
+          })}
+        >
           <Input
             id="value"
             type="number"
@@ -490,14 +488,14 @@ export function MeasurementForm({
             aria-invalid={!!error || undefined}
             aria-describedby={errorDescriptor}
           />
-        </div>
+        </FieldGroup>
       )}
 
       {isGlucoseMode && (
-        <div className="space-y-2">
-          <Label htmlFor="glucose-context">
-            {t("measurements.glucoseContext")}
-          </Label>
+        <FieldGroup
+          htmlFor="glucose-context"
+          label={t("measurements.glucoseContext")}
+        >
           <Select
             value={glucoseContext}
             onValueChange={(v) => setGlucoseContext(v as GlucoseContextValue)}
@@ -513,11 +511,17 @@ export function MeasurementForm({
               ))}
             </SelectContent>
           </Select>
-        </div>
+        </FieldGroup>
       )}
 
-      <div className="space-y-2">
-        <Label htmlFor="measuredAt">{t("measurements.timestamp")}</Label>
+      <FieldGroup
+        htmlFor="measuredAt"
+        label={t("measurements.timestamp")}
+        // v1.17.1 — surface that the timestamp is editable. The picker
+        // already defaults to now and accepts any earlier instant; many
+        // users never notice they can backdate a reading.
+        hint={t("measurements.timestampBackdateHint")}
+      >
         <DateTimeField
           id="measuredAt"
           value={measuredAt}
@@ -531,26 +535,24 @@ export function MeasurementForm({
           aria-invalid={!!error || undefined}
           aria-describedby={errorDescriptor}
         />
-        {/* v1.17.1 — surface that the timestamp is editable. The picker
-            already defaults to now and accepts any earlier instant; many
-            users never notice they can backdate a reading. */}
-        <p className="text-muted-foreground text-xs">
-          {t("measurements.timestampBackdateHint")}
-        </p>
-      </div>
+      </FieldGroup>
 
-      <div className="space-y-2">
-        <div className="flex items-center justify-between gap-3">
-          <Label htmlFor="notes">
+      <FieldGroup
+        htmlFor="notes"
+        label={
+          <>
             {t("measurements.notes")}{" "}
             <span className="text-muted-foreground font-normal">
               ({t("common.optional")})
             </span>
-          </Label>
+          </>
+        }
+        labelAccessory={
           <span className="text-muted-foreground text-xs">
             {notes.length}/{MAX_COMMENT_LENGTH}
           </span>
-        </div>
+        }
+      >
         <Input
           id="notes"
           value={notes}
@@ -560,7 +562,7 @@ export function MeasurementForm({
           enterKeyHint="done"
           autoCapitalize="sentences"
         />
-      </div>
+      </FieldGroup>
 
       {error && (
         <div

src/components/mood/mood-form.tsx

@@ -23,6 +23,7 @@ import {
 import { Input } from "@/components/ui/input";
 import { Textarea } from "@/components/ui/textarea";
 import { DateTimeField } from "@/components/ui/date-time-field";
+import { FieldGroup } from "@/components/ui/field-group";
 import { Label } from "@/components/ui/label";
 import {
   ListChecks,
@@ -473,17 +474,20 @@ export function MoodForm({ onSuccess, onCancel, footerSlot }: MoodFormProps) {
             </div>
 
             {/* v1.8.5 (C1) — free-text note. */}
-            <div className="space-y-2">
-              <div className="flex items-center justify-between gap-3">
-                <Label htmlFor="mood-note">
+            <FieldGroup
+              htmlFor="mood-note"
+              label={
+                <>
                   {t("mood.note")}{" "}
                   <span className="text-muted-foreground font-normal">
                     ({t("common.optional")})
                   </span>
-                </Label>
-                {/* v1.11.5 — character counter so the `maxLength` cap no
+                </>
+              }
+              labelAccessory={
+                /* v1.11.5 — character counter so the `maxLength` cap no
                 longer truncates silently. Turns destructive (warns) as the
-                input approaches the limit. */}
+                input approaches the limit. */
                 <span
                   data-testid="mood-note-counter"
                   className={`text-xs tabular-nums ${
@@ -498,7 +502,8 @@ export function MoodForm({ onSuccess, onCancel, footerSlot }: MoodFormProps) {
                     max: String(NOTE_MAX_LENGTH),
                   })}
                 </span>
-              </div>
+              }
+            >
               <Textarea
                 id="mood-note"
                 value={note}
@@ -507,10 +512,9 @@ export function MoodForm({ onSuccess, onCancel, footerSlot }: MoodFormProps) {
                 maxLength={NOTE_MAX_LENGTH}
                 rows={3}
               />
-            </div>
+            </FieldGroup>
 
-            <div className="space-y-2">
-              <Label htmlFor="mood-logged-at">{t("mood.timestamp")}</Label>
+            <FieldGroup htmlFor="mood-logged-at" label={t("mood.timestamp")}>
               <DateTimeField
                 id="mood-logged-at"
                 value={moodLoggedAt}
@@ -522,7 +526,7 @@ export function MoodForm({ onSuccess, onCancel, footerSlot }: MoodFormProps) {
                 aria-invalid={!!error || undefined}
                 aria-describedby={errorDescriptor}
               />
-            </div>
+            </FieldGroup>
           </SheetSection>
         </div>
       )}

src/components/onboarding/baseline-form.tsx

@@ -9,8 +9,8 @@ import { Loader2 } from "lucide-react";
 
 import { Button } from "@/components/ui/button";
 import { DateField } from "@/components/ui/date-field";
+import { FieldGroup } from "@/components/ui/field-group";
 import { Input } from "@/components/ui/input";
-import { Label } from "@/components/ui/label";
 import {
   Select,
   SelectContent,
@@ -170,10 +170,11 @@ export function BaselineForm() {
       <fieldset className="bg-card border-border space-y-5 rounded-xl border p-5">
         <legend className="sr-only">{t("onboarding.baseline.title")}</legend>
 
-        <div className="space-y-2">
-          <Label htmlFor="ob-baseline-display-name">
-            {t("onboarding.baseline.displayNameLabel")}
-          </Label>
+        <FieldGroup
+          htmlFor="ob-baseline-display-name"
+          label={t("onboarding.baseline.displayNameLabel")}
+          hint={t("onboarding.baseline.displayNameHint")}
+        >
           <Input
             id="ob-baseline-display-name"
             value={form.displayName}
@@ -182,16 +183,13 @@ export function BaselineForm() {
             maxLength={50}
             placeholder={t("onboarding.baseline.displayNamePlaceholder")}
           />
-          <p className="text-muted-foreground text-xs">
-            {t("onboarding.baseline.displayNameHint")}
-          </p>
-        </div>
+        </FieldGroup>
 
         <div className="grid gap-4 sm:grid-cols-2">
-          <div className="space-y-2">
-            <Label htmlFor="ob-baseline-height">
-              {t("onboarding.baseline.heightLabel")}
-            </Label>
+          <FieldGroup
+            htmlFor="ob-baseline-height"
+            label={t("onboarding.baseline.heightLabel")}
+          >
             <Input
               id="ob-baseline-height"
               type="number"
@@ -204,11 +202,11 @@ export function BaselineForm() {
               step={0.1}
               autoComplete="off"
             />
-          </div>
-          <div className="space-y-2">
-            <Label htmlFor="ob-baseline-gender">
-              {t("onboarding.baseline.genderLabel")}
-            </Label>
+          </FieldGroup>
+          <FieldGroup
+            htmlFor="ob-baseline-gender"
+            label={t("onboarding.baseline.genderLabel")}
+          >
             <Select
               // The design system's Radix Select uses an empty-string
               // sentinel to mean "no selection"; map back and forth so
@@ -235,13 +233,14 @@ export function BaselineForm() {
                 </SelectItem>
               </SelectContent>
             </Select>
-          </div>
+          </FieldGroup>
         </div>
 
-        <div className="space-y-2">
-          <Label htmlFor="ob-baseline-dob">
-            {t("onboarding.baseline.dateOfBirthLabel")}
-          </Label>
+        <FieldGroup
+          htmlFor="ob-baseline-dob"
+          label={t("onboarding.baseline.dateOfBirthLabel")}
+          hint={t("onboarding.baseline.dateOfBirthHint")}
+        >
           <DateField
             id="ob-baseline-dob"
             value={form.dateOfBirth}
@@ -249,10 +248,7 @@ export function BaselineForm() {
             max={new Date().toISOString().slice(0, 10)}
             autoComplete="bday"
           />
-          <p className="text-muted-foreground text-xs">
-            {t("onboarding.baseline.dateOfBirthHint")}
-          </p>
-        </div>
+        </FieldGroup>
       </fieldset>
 
       <AnamnesisCard

src/components/ui/field-group.tsx

@@ -0,0 +1,51 @@
+import type { ReactNode } from "react";
+
+import { Label } from "@/components/ui/label";
+import { cn } from "@/lib/utils";
+
+/**
+ * Central form field-group primitive: one label-above-control rhythm so every
+ * add form reads with the same vertical spacing. Mirrors the long-standing
+ * `space-y-2` + `<Label htmlFor>` + control idiom byte-for-byte so adopting it
+ * is a no-op on rendered output.
+ *
+ * - `hint` renders below the control as muted fine print.
+ * - `labelAccessory` sits right-aligned in the label row (e.g. a char counter);
+ *   when present the label row becomes a `justify-between` flex row.
+ */
+export function FieldGroup({
+  htmlFor,
+  label,
+  hint,
+  labelAccessory,
+  className,
+  labelClassName,
+  children,
+}: {
+  htmlFor: string;
+  label: ReactNode;
+  hint?: ReactNode;
+  labelAccessory?: ReactNode;
+  className?: string;
+  labelClassName?: string;
+  children: ReactNode;
+}) {
+  return (
+    <div className={cn("space-y-2", className)}>
+      {labelAccessory ? (
+        <div className="flex items-center justify-between gap-3">
+          <Label htmlFor={htmlFor} className={labelClassName}>
+            {label}
+          </Label>
+          {labelAccessory}
+        </div>
+      ) : (
+        <Label htmlFor={htmlFor} className={labelClassName}>
+          {label}
+        </Label>
+      )}
+      {children}
+      {hint ? <p className="text-muted-foreground text-xs">{hint}</p> : null}
+    </div>
+  );
+}