FIX: report unknown planned for an empty count combination

pyrit/analytics/scenario_statistics.py

@@ -523,7 +523,13 @@ def combine_execution_counts(counts: Iterable[ScenarioProgressCounts]) -> Scenar
 
     return ScenarioProgressCounts(
         completed=completed,
-        planned=sum(value for value in planned if value is not None) if all(v is not None for v in planned) else None,
+        planned=(
+            # The empty group carries no plan at all, so it reports None rather
+            # than a vacuous sum() of 0.
+            sum(value for value in planned if value is not None)
+            if planned and all(v is not None for v in planned)
+            else None
+        ),
         succeeded=succeeded,
         success_percentage=success_percentage(succeeded=succeeded, completed=completed),
         errors=sum(item.errors for item in counts),

tests/unit/analytics/test_scenario_statistics.py

@@ -142,6 +142,13 @@ def test_combining_count_only_legacy_payloads_does_not_infer_failures_from_histo
     assert "without an outcome breakdown" in caplog.text
 
 
+def test_combining_an_empty_group_reports_no_planned_count() -> None:
+    """An empty display group never learned a plan, so planned is unknown, not 0."""
+    combined = combine_execution_counts([])
+    assert combined.planned is None
+    assert combined.completed == 0
+
+
 def test_combining_unequal_scenario_groups_recomputes_both_denominators() -> None:
     result = make_scenario_result(
         attack_results={