fix(dashboard): show the blood pressure axis in mmHg, not Hg

The dashboard's blood pressure chart passed `yAxisUnit="Hg"` beside
`unit="mmHg"`, a shortening carried since the first release, so every
tick read "154 Hg". The override is gone; "mmHg" is four characters and
fits the axis gutter like "bpm" and "mg/dL" do.

A unit with a space of its own ("/ 5") is now joined with no-break
spaces as well, so Recharts cannot wrap it either. A guard fails on any
`yAxisUnit` that is a cut-down form of the `unit` beside it.

src/app/page-client.tsx

@@ -1780,7 +1780,6 @@ export default function DashboardPageClient({
                 title={t("dashboard.bloodPressure")}
                 colors={["var(--chart-3)", "var(--chart-4)"]}
                 unit="mmHg"
-                yAxisUnit="Hg"
                 targetZones={bpTargetZones}
                 compareBaseline={compareBaseline}
                 userTimezone={user?.timezone}

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

@@ -39,6 +39,11 @@ describe("axis unit suffix", () => {
     expect(axisUnitSuffix(null)).toBeUndefined();
   });
 
+  it("keeps a unit with a space of its own on one line", () => {
+    expect(axisUnitSuffix("/ 5")).toBe("\u00a0/\u00a05");
+    expect(axisUnitSuffix("mmHg")).toBe("\u00a0mmHg");
+  });
+
   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);
@@ -55,6 +60,59 @@ describe("axis unit suffix", () => {
   });
 });
 
+/**
+ * Every tag in the app that names both a `unit` and a `yAxisUnit` literal.
+ * The dashboard's blood pressure chart carried `yAxisUnit="Hg"` beside
+ * `unit="mmHg"` from the first release on, so its axis read "154 Hg".
+ */
+function axisUnitOverrides(): Array<{
+  file: string;
+  unit: string;
+  axis: string;
+}> {
+  const out: Array<{ file: string; unit: string; axis: string }> = [];
+  for (const root of ["app", "components"]) {
+    const dir = join(process.cwd(), "src", root);
+    for (const rel of walkSourceFiles(dir, {
+      floor: 100,
+      extensions: [".tsx"],
+    })) {
+      if (rel.includes("__tests__")) continue;
+      const src = stripComments(readFileSync(join(dir, rel), "utf8"));
+      // The tag around each override: back to the previous element's end,
+      // forward to the next one's. A prop holding JSX (`icon={<X />}`) can
+      // sit inside, so the tag is not cut at the first `<`.
+      for (const m of src.matchAll(/\byAxisUnit="([^"]*)"/g)) {
+        const before = src.slice(0, m.index);
+        const from = Math.max(0, before.lastIndexOf("/>"), m.index - 1500);
+        const afterEnd = src.indexOf("/>", m.index);
+        const tag = src.slice(from, afterEnd === -1 ? undefined : afterEnd);
+        const unit = /\bunit="([^"]*)"/.exec(tag);
+        if (unit)
+          out.push({ file: `${root}/${rel}`, unit: unit[1], axis: m[1] });
+      }
+    }
+  }
+  return out;
+}
+
+describe("axis unit overrides", () => {
+  it("finds the overrides it is meant to police", () => {
+    expect(axisUnitOverrides().length).toBeGreaterThanOrEqual(5);
+  });
+
+  it("never cuts a unit short on the axis", () => {
+    const cut = axisUnitOverrides()
+      .filter(
+        ({ unit, axis }) => axis !== "" && axis !== unit && unit.includes(axis),
+      )
+      .map(
+        ({ file, unit, axis }) => `${file}: unit="${unit}" yAxisUnit="${axis}"`,
+      );
+    expect(cut).toEqual([]);
+  });
+});
+
 describe("axisTickUnitSuffix", () => {
   it("keeps a short unit on the ticks", () => {
     expect(axisTickUnitSuffix("bpm")).toBe(axisUnitSuffix("bpm"));

src/lib/charts/axis-unit.ts

@@ -11,7 +11,8 @@
 export function axisUnitSuffix(
   unit: string | null | undefined,
 ): string | undefined {
-  return unit ? ` ${unit}` : undefined;
+  // A space inside the unit ("/ 5") would break the label the same way.
+  return unit ? ` ${unit.replace(/ /g, "\u00a0")}` : undefined;
 }
 
 /**