ci(ascend): enable PR validation

Author: HermiaHuan

.github/configs/platforms.yml

@@ -23,9 +23,9 @@ platforms:
   cuda:
     enabled: true
   ascend:
-    # Ascend uses a scarce self-hosted NPU runner. Run it explicitly through
-    # the "Ascend Manual CI" workflow after host-side smoke validation.
-    enabled: false
+    # Ascend uses a scarce self-hosted NPU runner; keep it enabled when
+    # validating Ascend changes in PR CI.
+    enabled: true
   hygon:
     enabled: true
   metax: