feat: add uses_grounded_selector strategy switch (AR only)

app/question_gen/strategy.py

@@ -91,6 +91,9 @@ class TaskTypeStrategy(Protocol):
     @property
     def leak_probe_template(self) -> str: ...
 
+    @property
+    def uses_grounded_selector(self) -> bool: ...
+
     def select_sub_pattern(self, rng: random.Random) -> SubPattern | None: ...
 
     def build_prompt_context(self, material: Any, sub_pattern: SubPattern | None) -> dict: ...
@@ -168,6 +171,11 @@ class BaseTaskTypeStrategy:
         """返回泄漏探测模板文件名（委托给绑定的 family.leak_profile）。"""
         return self._family.leak_profile.probe_template
 
+    @property
+    def uses_grounded_selector(self) -> bool:
+        """默认不启用 grounded selector（11 类题型走原路径）。"""
+        return False
+
     def select_sub_pattern(self, rng: random.Random) -> SubPattern | None:
         """BaseTaskTypeStrategy 无子模式。"""
         return None