feat: add uses_grounded_selector strategy switch (AR only)

tests/unit/test_strategy_grounded_flag.py

@@ -0,0 +1,19 @@
+"""uses_grounded_selector 分流：仅 AR=True，其余 11 类=False。"""
+
+from app.question_gen.strategy import get_strategy
+
+_NON_AR = [
+    "Action Reasoning", "Attribute Perception", "Counting Problem",
+    "Information Synopsis", "Object Recognition", "Object Reasoning",
+    "OCR Problems", "Spatial Perception", "Spatial Reasoning",
+    "Temporal Perception", "Temporal Reasoning",
+]
+
+
+def test_action_recognition_uses_grounded_selector():
+    assert get_strategy("Action Recognition").uses_grounded_selector is True
+
+
+def test_non_ar_do_not_use_grounded_selector():
+    for tt in _NON_AR:
+        assert get_strategy(tt).uses_grounded_selector is False, tt