Refine prompt_template_source: cite verifiable official sources per 2026-05-30 deep audit

metadata.json

@@ -52,9 +52,9 @@
         }
       },
       "prompt_template_source": {
-        "origin": "fallback",
-        "reference": "T3-adapted",
-        "notes": "MCQ-shape per-dataset adaptation"
+        "origin": "official",
+        "reference": "https://github.com/EvolvingLMMs-Lab/lmms-eval/blob/main/lmms_eval/tasks/dynamath/utils.py (dynamath_doc_to_text — image+question+optional Options:/A./B. trailer)",
+        "notes": "lmms-eval DynaMath canonical evaluation prompt."
       }
     }
   }