fix: address widget review feedback

packages/widgets/src/beszel-system-stats/selection.spec.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from "vitest";
 
-import { createBeszelSystemChoices, resolveBeszelSystemChoice } from "./selection";
+import { createBeszelSystemChoices, resolveBeszelSystemChoice, resolveStoredBeszelQuerySelection } from "./selection";
 
 const choices = createBeszelSystemChoices([
   { integrationId: "one", integrationName: "Primary", systems: [{ id: "same", name: "Host A" }] },
@@ -13,7 +13,34 @@ describe("Beszel system selection", () => {
     expect(resolveBeszelSystemChoice(choices, "two:same")?.integrationId).toBe("two");
   });
 
-  it("keeps legacy plain system ids working", () => {
-    expect(resolveBeszelSystemChoice(choices, "same")?.integrationId).toBe("one");
+  it("keeps unique legacy plain system ids working", () => {
+    expect(resolveBeszelSystemChoice(choices.slice(0, 1), "same")?.integrationId).toBe("one");
+  });
+
+  it("defaults an empty selection to the first system", () => {
+    expect(resolveBeszelSystemChoice(choices, "")?.integrationId).toBe("one");
+  });
+
+  it("does not guess when a legacy plain system id is ambiguous", () => {
+    expect(resolveBeszelSystemChoice(choices, "same")).toBeUndefined();
+  });
+
+  it("does not silently replace an unresolved stored system", () => {
+    expect(resolveBeszelSystemChoice(choices, "missing")).toBeUndefined();
+  });
+
+  it("derives the queried integration and system from a composite selection", () => {
+    expect(resolveStoredBeszelQuerySelection("two:same", ["one", "two"])).toEqual({
+      integrationIds: ["two"],
+      systemId: "same",
+    });
+  });
+
+  it("supports a legacy plain system id only when the integration is unambiguous", () => {
+    expect(resolveStoredBeszelQuerySelection("same", ["one"])).toEqual({
+      integrationIds: ["one"],
+      systemId: "same",
+    });
+    expect(resolveStoredBeszelQuerySelection("same", ["one", "two"])).toBeNull();
   });
 });