fix(charts): keep axis unit labels on one line; 44 px date and time triggers

Recharts word-wraps a tick label that it measures wider than its axis,
and it measures in the page's body font rather than the tick's 11 px.
"62 bpm" on the pulse chart under a workout and "106 mg/dL" on the
glucose page therefore broke onto two lines at every width, and the
pulse chart's second line sat on the first x tick. Axis units are now
joined with a no-break space through `axisUnitSuffix`, so the label is
one word and stays on one line. A guard fails when a chart axis joins a
unit with a plain space.

The calendar and clock buttons in the date and time fields paint at
32 px; a `::before` halo now gives them a 44 px touch target without
changing the field.

src/components/charts/health-chart.tsx

@@ -71,6 +71,7 @@ import {
   type MetricWindowStats,
 } from "@/lib/charts/window-stats";
 import { shouldFireDataReady } from "@/lib/charts/data-ready-latch";
+import { axisUnitSuffix } from "@/lib/charts/axis-unit";
 
 // The range tabs select a CALENDAR-DAY window ending now — `days: 7` is
 // "the last 7 days", not "the last 7 readings". The labels said "points"
@@ -1982,8 +1983,8 @@ export function HealthChart({
                         : String(value)
                     }
                     unit={
-                      showYAxisUnit && (yAxisUnit ?? unit)
-                        ? ` ${yAxisUnit ?? unit}`
+                      showYAxisUnit
+                        ? axisUnitSuffix(yAxisUnit ?? unit)
                         : undefined
                     }
                   />

src/components/insights/intraday-pulse-chart.tsx

@@ -24,6 +24,7 @@ import { TileHeader } from "@/components/insights/tile-header";
 import { Button } from "@/components/ui/button";
 import { QueryErrorCard } from "@/components/ui/query-error-card";
 import { Skeleton } from "@/components/ui/skeleton";
+import { axisUnitSuffix } from "@/lib/charts/axis-unit";
 import {
   BUCKET_MINUTES,
   type IntradayHrBucket,
@@ -300,7 +301,7 @@ export function IntradayPulseChart({
                 tick={{ fontSize: 11, fill: "var(--muted-foreground)" }}
                 tickLine={false}
                 axisLine={false}
-                unit=" bpm"
+                unit={axisUnitSuffix("bpm")}
                 width={52}
               />
               <Tooltip

src/components/medications/detail/efficacy/efficacy-chart.tsx

@@ -26,6 +26,7 @@ import {
 } from "recharts";
 import { makeFormatters } from "@/lib/format-locale";
 import { useDateFormatPreference, useTranslations } from "@/lib/i18n/context";
+import { axisUnitSuffix } from "@/lib/charts/axis-unit";
 
 export interface EfficacyChartTarget {
   label: string;
@@ -169,7 +170,7 @@ export function EfficacyChart({
             tickLine={false}
             axisLine={false}
             width={40}
-            unit={unitSuffix ? ` ${unitSuffix}` : undefined}
+            unit={axisUnitSuffix(unitSuffix)}
           />
           <YAxis
             yAxisId="adherence"

src/components/ui/__tests__/date-field.test.tsx

@@ -93,6 +93,19 @@ describe("<DateField>", () => {
     expect(html).toContain("sm:h-10");
   });
 
+  it("gives the calendar button a 44 px touch target at its 32 px size", () => {
+    const html = render(<DateField value="2026-02-19" />);
+    const button = /<button[^>]*aria-label="Open date picker"[^>]*>/.exec(
+      html,
+    )?.[0];
+    expect(button).toBeDefined();
+    // Painted size unchanged; the ::before halo adds 6 px per edge.
+    expect(button).toContain("h-8 w-8");
+    expect(button).toContain("relative");
+    expect(button).toContain("before:-inset-1.5");
+    expect(button).toContain("before:absolute");
+  });
+
   it("exposes a labelled calendar picker affordance", () => {
     const html = render(<DateField value="2026-02-19" />);
     expect(html).toContain('aria-label="Open date picker"');

src/components/ui/__tests__/time-field.test.tsx

@@ -105,6 +105,18 @@ describe("formatHhmm", () => {
 });
 
 describe("<TimeField> SSR", () => {
+  it("gives the clock button a 44 px touch target at its 32 px size", () => {
+    const html = render(<TimeField value="14:05" />, "de");
+    const button = /<button[^>]*data-slot="time-field-trigger"[^>]*>/.exec(
+      html,
+    )?.[0];
+    expect(button).toBeDefined();
+    expect(button).toContain("h-8 w-8");
+    expect(button).toContain("relative");
+    expect(button).toContain("before:-inset-1.5");
+    expect(button).toContain("before:absolute");
+  });
+
   it("paints the value in 24h under the de AUTO locale and exposes the picker affordance", () => {
     const html = render(<TimeField value="14:05" />, "de");
     expect(html).toContain('value="14:05"');

src/components/ui/date-field.tsx

@@ -225,7 +225,9 @@ export const DateField = React.forwardRef<HTMLInputElement, DateFieldProps>(
               type="button"
               disabled={disabled}
               aria-label={t("common.openDatePicker")}
-              className="text-muted-foreground hover:text-foreground flex h-8 w-8 shrink-0 items-center justify-center rounded-md disabled:cursor-not-allowed disabled:opacity-50"
+              // The button paints at 32 px; the `::before` halo (6 px per edge)
+              // makes the touch target 44 px without changing the field.
+              className="text-muted-foreground hover:text-foreground relative flex h-8 w-8 shrink-0 items-center justify-center rounded-md before:absolute before:-inset-1.5 before:content-[''] disabled:cursor-not-allowed disabled:opacity-50"
             >
               <CalendarIcon className="h-4 w-4" aria-hidden="true" />
             </button>

src/components/ui/time-field.tsx

@@ -189,7 +189,9 @@ export const TimeField = React.forwardRef<HTMLInputElement, TimeFieldProps>(
               tabIndex={-1}
               disabled={disabled}
               aria-label={t("common.openTimePicker")}
-              className="text-muted-foreground hover:text-foreground flex h-8 w-8 shrink-0 items-center justify-center rounded-md disabled:cursor-not-allowed disabled:opacity-50"
+              // The button paints at 32 px; the `::before` halo (6 px per edge)
+              // makes the touch target 44 px without changing the field.
+              className="text-muted-foreground hover:text-foreground relative flex h-8 w-8 shrink-0 items-center justify-center rounded-md before:absolute before:-inset-1.5 before:content-[''] disabled:cursor-not-allowed disabled:opacity-50"
               data-slot="time-field-trigger"
             >
               <Clock className="h-4 w-4" aria-hidden="true" />

src/lib/charts/__tests__/axis-unit.test.ts

@@ -0,0 +1,56 @@
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+
+import { describe, expect, it } from "vitest";
+
+import {
+  stripComments,
+  walkSourceFiles,
+} from "@/__tests__/helpers/source-files";
+import { axisUnitSuffix } from "../axis-unit";
+
+const COMPONENTS = join(process.cwd(), "src", "components");
+
+/**
+ * Every `<XAxis … />` / `<YAxis … />` tag's `unit=` value in the tree. The tag
+ * runs to its `/>`: stopping at the first `>` would end it inside an arrow
+ * function prop and miss a `unit` written after one.
+ */
+function axisUnitProps(): Array<{ file: string; value: string }> {
+  const out: Array<{ file: string; value: string }> = [];
+  for (const rel of walkSourceFiles(COMPONENTS, {
+    floor: 300,
+    extensions: [".tsx"],
+  })) {
+    if (rel.includes("__tests__")) continue;
+    const src = stripComments(readFileSync(join(COMPONENTS, rel), "utf8"));
+    for (const tag of src.matchAll(/<[XY]Axis\b[\s\S]*?\/>/g)) {
+      const unit = /\bunit=(\{[\s\S]*?\}|"[^"]*")/.exec(tag[0]);
+      if (unit) out.push({ file: rel, value: unit[1] });
+    }
+  }
+  return out;
+}
+
+describe("axis unit suffix", () => {
+  it("joins the unit with a no-break space", () => {
+    expect(axisUnitSuffix("bpm")).toBe(" bpm");
+    expect(axisUnitSuffix("")).toBeUndefined();
+    expect(axisUnitSuffix(null)).toBeUndefined();
+  });
+
+  it("finds the axis units it is meant to police", () => {
+    // A matcher that finds nothing would pass the check below by default.
+    expect(axisUnitProps().length).toBeGreaterThanOrEqual(6);
+  });
+
+  it("no chart axis joins a unit with a breaking space", () => {
+    // Recharts wraps a tick label at a breaking space when it measures the
+    // label wider than the axis, and it measures in the body font: "62 bpm"
+    // broke onto two lines and its second line sat on the first x tick.
+    const offenders = axisUnitProps()
+      .filter(({ value }) => /["`] /.test(value))
+      .map(({ file, value }) => `${file}: unit=${value}`);
+    expect(offenders).toEqual([]);
+  });
+});

src/lib/charts/axis-unit.ts

@@ -0,0 +1,15 @@
+/**
+ * The unit suffix a chart axis appends to each tick value ("62 bpm").
+ *
+ * Joined with a no-break space, never a plain one. Recharts word-wraps a
+ * tick label that is wider than the axis, and it measures the label in the
+ * page's body font rather than the tick's own 11 px, so "62 bpm" and
+ * "106 mg/dL" measured wider than their axis and broke onto two lines on
+ * every screen. The second line dropped onto the first x tick. A label with
+ * no breaking space is one word and stays on one line.
+ */
+export function axisUnitSuffix(
+  unit: string | null | undefined,
+): string | undefined {
+  return unit ? ` ${unit}` : undefined;
+}