Return null for unknown type in getStateData to prevent empty URL request

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/stores/compare.ts

@@ -55,6 +55,8 @@ export const useCompareStore = defineStore("compareStore", {
         case "filter":
           api = `/api/filters/${id}/discover`;
           break;
+        default:
+          return null;
       }
       try {
         const response = await apiClient.get(api);

tests/stores/compare.test.js

@@ -77,6 +77,13 @@ describe("compareStore", () => {
       expect(mockGet).toHaveBeenCalledWith("/api/filters/3/discover");
       expect(result).toEqual({ cases: 50 });
     });
+
+    it("returns null for unknown type", async () => {
+      const result = await store.getStateData("unknown", 1);
+
+      expect(mockGet).not.toHaveBeenCalled();
+      expect(result).toBeNull();
+    });
   });
 
   describe("getFileName", () => {