dubbo: enable Java-only residual prune

config/apache_dubbo_dubbo-3.3.3_dubbo-3.3.6.yaml

@@ -39,6 +39,14 @@ test_dirs:
 exclude:
   - "**/target/**"
 
+# Dubbo's agent-authoritative production sources are Java.  Make deletion
+# inference the repository default while statically preventing the generic
+# multi-language pruner from touching Groovy/Kotlin or other source types.
+residue_prune: true
+prune_extensions:
+  - ".java"
+prune_keep_list: []
+
 main_branch: "3.3"
 
 # Compile the complete Maven test source tree before grading. This activates