refactoring: add initial pipeline configuration and model classes

processing/steps/data_cleaning_step.py

@@ -0,0 +1,28 @@
+import logging
+
+import pandas as pd
+
+from core.config.pipeline_config import PipelineConfig
+from core.utils.text_cleaner import TextCleaner
+from processing.steps import PipelineStep
+
+
+class DataCleaningStep(PipelineStep):
+    """Configuration-driven data cleaning step"""
+
+    def __init__(self, pipeline_config: PipelineConfig):
+        super().__init__("data_cleaning", pipeline_config)
+        self.text_cleaner = TextCleaner()
+        self.required_columns = ["name", "sex", "region"]
+
+    def process_batch(self, batch: pd.DataFrame, batch_id: int) -> pd.DataFrame:
+        """Process a single batch for data cleaning"""
+        logging.info(f"Cleaning batch {batch_id} with {len(batch)} rows")
+
+        # Drop rows with essential missing values
+        batch = batch.dropna(subset=self.required_columns)
+
+        # Apply text cleaning
+        batch = self.text_cleaner.clean_dataframe_text_columns(batch)
+
+        return batch