test(apiserver): GetJobsInfo pagination returns every row once (bug-1903)

Follows page_token with limit=3 over the handler fixture. Before
efff6b65 the token's float-rounded array-element ID matched no row and
every page restarted at row 0 (the original repeat-the-first-page
report); it now pages through every row exactly once.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/frontend/apiserver/controllers/jobs_handler_test.go

@@ -1383,3 +1383,49 @@ func TestJobHandler_ControlFilterPlainNameWithSpaces(t *testing.T) {
 	assertExactIDs(t, "-J 'sleep 100' dispatched", f.dispatchedIDs(), []uint64{O})
 	assertExactIDs(t, "-J 'sleep 100' accepted", itemIDs(t, r.Accepted), []uint64{O})
 }
+
+// bug-1903: following GetJobsInfo's page_token yields the next page, every
+// row exactly once, and the last page carries no token.
+func TestJobHandler_QueryPagination(t *testing.T) {
+	f := newHandlerFixture(t)
+	s := seedQueryJobs(f)
+	filter := url.QueryEscape("{submit_user:eq:" + handlerTestUser + "}")
+
+	var got []uint64
+	token := ""
+	for page := 0; ; page++ {
+		if page > 10 {
+			t.Fatalf("paging did not terminate; rows so far %v", got)
+		}
+		path := "/xce/v1/jobs?limit=3&filter=" + filter
+		if token != "" {
+			path += "&page_token=" + url.QueryEscape(token)
+		}
+		w := f.do(http.MethodGet, path, nil)
+		got = append(got, rowIDs(t, w)...)
+
+		var reply struct {
+			Data struct {
+				PageToken string `json:"page_token"`
+			} `json:"data"`
+		}
+		if err := json.Unmarshal(w.Body.Bytes(), &reply); err != nil {
+			t.Fatalf("decode page_token: %v", err)
+		}
+		if reply.Data.PageToken == "" {
+			break
+		}
+		token = reply.Data.PageToken
+	}
+
+	seen := map[uint64]int{}
+	for _, id := range got {
+		seen[id]++
+	}
+	for id, n := range seen {
+		if n != 1 {
+			t.Errorf("row %d returned %d times", id, n)
+		}
+	}
+	assertIDs(t, "all pages", sortedIDs(got...), s.all())
+}