style(admin): reduce excessive vertical whitespace on Zielwerte page

Marc reported "relativ viel Platz" wasted between the overview
header and the first cards on `/targets` (Zielwerte). The page
used `space-y-8` (32 px) on the outer wrapper, which leaves an
oversized gap between the intro paragraph and the first card.

Tighten to `space-y-6` (24 px) — same rhythm the admin and
settings pages use, so the whole app shares one Dracula-spacing
beat.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/__tests__/targets-spacing.test.tsx

@@ -0,0 +1,65 @@
+import { describe, expect, it, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+
+/**
+ * v1.4.19 phase A7 — `/targets` (Zielwerte) had `space-y-8` between
+ * the page header (h1 + intro) and the first card grid. At Pixel-5
+ * Marc reported "relativ viel Platz" wasted between the overview
+ * and the first values. Tighten the rhythm to `space-y-6` (24px)
+ * which matches the rest of the admin / settings pages.
+ */
+
+vi.mock("next/navigation", () => ({
+  useRouter: () => ({ push: vi.fn(), replace: vi.fn() }),
+  usePathname: () => "/targets",
+}));
+
+vi.mock("@tanstack/react-query", () => ({
+  useQuery: () => ({
+    data: {
+      targets: [],
+      bpDiastolic: { current: null, average30: null, range: null },
+      profile: { heightCm: null, age: null, gender: null, glucoseUnit: null },
+    },
+    isLoading: false,
+    isError: false,
+    refetch: vi.fn(),
+  }),
+}));
+
+vi.mock("@/hooks/use-auth", () => ({
+  useAuth: () => ({
+    user: {
+      id: "u1",
+      username: "marc",
+      email: "marc@example.com",
+      role: "USER",
+    },
+    isAuthenticated: true,
+    isLoading: false,
+    refetch: vi.fn(),
+  }),
+}));
+
+import { I18nProvider } from "@/lib/i18n/context";
+import TargetsPage from "../targets/page";
+
+function render(locale: "en" | "de" = "en") {
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale={locale}>
+      <TargetsPage />
+    </I18nProvider>,
+  );
+}
+
+describe("/targets page — vertical spacing", () => {
+  it("uses space-y-6 (not space-y-8) between header and card grid", () => {
+    const html = render();
+    // Outer wrapper rhythm. `space-y-8` would leave ~32px of
+    // unnecessary breathing room between the intro paragraph and the
+    // first card; `space-y-6` (24px) brings it in line with the
+    // admin / settings pages.
+    expect(html).toMatch(/<div[^>]*\bspace-y-6\b/);
+    expect(html).not.toMatch(/<div[^>]*\bspace-y-8\b/);
+  });
+});

src/app/targets/page.tsx

@@ -549,7 +549,11 @@ export default function TargetsPage() {
     });
 
   return (
-    <div className="space-y-8">
+    // v1.4.19 phase A7 — Marc reported "relativ viel Platz" wasted
+    // between the overview header and the first values on `/targets`.
+    // Tighten the rhythm from `space-y-8` (32 px) to `space-y-6`
+    // (24 px) — that matches the admin / settings pages.
+    <div className="space-y-6">
       <div>
         <h1 className="text-2xl font-bold">{t("targets.title")}</h1>
         <p className="mt-2 text-sm">{t("targets.introText")}</p>