Add parametric walls unit tests

50 Vitest-Tests für die parametrische Wand-Engine (src/model/parametricWalls.ts):
GridRule, ModuleRule, ConditionalThicknessRule, ReferenceLineRule, SequenceRule,
deduplicateWalls, matchesCondition/matchesTarget, Integration via resolveParametricWall.
Vitest als devDependency + Testskript in package.json + vitest.config.ts ergänzt.

vitest.config.ts

@@ -0,0 +1,8 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    environment: "node",
+    include: ["src/**/*.test.ts"],
+  },
+});