fix: in JobTransformerBase, prevent configuring pads twice and prevent configuring invalid pads

Author: silenium-dev

Diff for: src/main/kotlin/dev/silenium/libs/flows/base/JobTransformerBase.kt

@@ -20,11 +20,16 @@ abstract class JobTransformerBase<IT, IP, OT, OP>(
     protected var job: Job? = null
 
     override fun configure(pad: UInt, metadata: IP): Result<Unit> {
+        if (!inputMetadata_.containsKey(pad)) return Result.failure(IllegalStateException("pad already configured"))
+        if (pads?.contains(pad) == false) return Result.failure(IllegalStateException("pad not allowed"))
+
         inputMetadata_[pad] = metadata
         outputMetadata_[pad] = outputMetadata(metadata)
+
         if (pads?.equals(inputMetadata_.keys) == true) {
             job = coroutineScope.launch { run() }
         }
+
         return Result.success(Unit)
     }