Fix manual company switch route sync

Co-Authored-By: Paperclip <noreply@paperclip.ing>

ui/src/lib/company-selection.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, it } from "vitest";
+import { shouldSyncCompanySelectionFromRoute } from "./company-selection";
+
+describe("shouldSyncCompanySelectionFromRoute", () => {
+  it("does not resync when selection already matches the route", () => {
+    expect(
+      shouldSyncCompanySelectionFromRoute({
+        selectionSource: "route_sync",
+        selectedCompanyId: "pap",
+        routeCompanyId: "pap",
+      }),
+    ).toBe(false);
+  });
+
+  it("defers route sync while a manual company switch is in flight", () => {
+    expect(
+      shouldSyncCompanySelectionFromRoute({
+        selectionSource: "manual",
+        selectedCompanyId: "pap",
+        routeCompanyId: "ret",
+      }),
+    ).toBe(false);
+  });
+
+  it("syncs back to the route company for non-manual mismatches", () => {
+    expect(
+      shouldSyncCompanySelectionFromRoute({
+        selectionSource: "route_sync",
+        selectedCompanyId: "pap",
+        routeCompanyId: "ret",
+      }),
+    ).toBe(true);
+  });
+});