test: Skalen-Paritätstest liest das Backend-Fixture erst im Test

Im Frontend-Image fehlt der Backend-Ordner; describe.skipIf führt den
Rumpf beim Sammeln trotzdem aus, das readFileSync dort brach den Build
ab (ENOENT). Das Fixture wird jetzt im Test gelesen.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Frontend/src/lib/inspections/scales.spec.ts

@@ -29,10 +29,15 @@ const GOOD_STORED_END: Record<InspectionScaleField, 1 | 5> = {
 };
 
 // The frontend image builds without the backend folder: then there is nothing to compare.
+// The callback of a skipped describe still runs while collecting, so the file
+// is read lazily inside the tests.
+const readFixture = (): ScaleFixture[] =>
+  JSON.parse(readFileSync(FIXTURE_PATH, "utf8")) as ScaleFixture[];
+
 describe.skipIf(!existsSync(FIXTURE_PATH))("inspection scales", () => {
-  const fixture = JSON.parse(readFileSync(FIXTURE_PATH, "utf8")) as ScaleFixture[];
 
   it("scale directions equal the shared fixture", () => {
+    const fixture = readFixture();
     expect(Object.keys(INSPECTION_SCALE_DIRECTIONS).sort()).toEqual(
       fixture.map((scale) => scale.field).sort(),
     );