fix dashboard validation fallback and semantic relation parsing

backend/src/services/resource_service.py

@@ -189,15 +189,36 @@ class ResourceService:
             )
             return self._normalize_datetime_for_compare(raw_time)
 
-        last_task = max(matched_tasks, key=_task_time)
-        raw_result = getattr(last_task, "result", None)
-        validation_status = None
-        if isinstance(raw_result, dict):
-            validation_status = self._normalize_validation_status(raw_result.get("status"))
+        projected_tasks = []
+        for task in matched_tasks:
+            raw_result = getattr(task, "result", None)
+            validation_status = None
+            if isinstance(raw_result, dict):
+                validation_status = self._normalize_validation_status(raw_result.get("status"))
+            projected_tasks.append(
+                (
+                    task,
+                    validation_status,
+                    _task_time(task),
+                )
+            )
+
+        projected_tasks.sort(key=lambda item: item[2], reverse=True)
+        latest_task, latest_validation_status, _ = projected_tasks[0]
+        decisive_task = next(
+            (
+                item for item in projected_tasks
+                if item[1] in {"PASS", "WARN", "FAIL"}
+            ),
+            None,
+        )
+        validation_status = latest_validation_status
+        if validation_status == "UNKNOWN" and decisive_task is not None:
+            validation_status = decisive_task[1]
 
         return {
-            "task_id": str(getattr(last_task, "id", "")),
-            "status": self._normalize_task_status(getattr(last_task, "status", "")),
+            "task_id": str(getattr(latest_task, "id", "")),
+            "status": self._normalize_task_status(getattr(latest_task, "status", "")),
             "validation_status": validation_status,
         }
     # [/DEF:_get_last_llm_task_for_dashboard:Function]