feat: Add consolidation support to incremental migration

Previously incremental migration (both timestamp-based and ID-based) did not
consolidate rows, resulting in one row per node instead of consolidated
measurements with JSONB nodes.

Solution: Add _consolidate_batch() method to group rows by consolidation key
and consolidate them before transformation. Apply consolidation in both:
1. _migrate_by_timestamp() - timestamp-based incremental migration
2. _migrate_by_id() - ID-based incremental migration

Changes:
- For RAWDATACOR and ELABDATADISP tables: consolidate batch by grouping rows
  with same consolidation key before transforming
- Pass consolidate=False to transform_batch since rows are already consolidated
- Handle cases where batch has single rows (no consolidation needed)

This ensures incremental migration produces the same consolidated output as
full migration, with multiple nodes properly merged into single row with JSONB
measurements.

🤖 Generated with Claude Code

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/migrator/incremental_migration.py

@@ -158,6 +158,8 @@ class IncrementalMigrator:
 
         # Fetch and migrate rows in batches
         batch_count = 0
+        progress = None
+
         for batch in mysql_conn.fetch_rows_since(
             mysql_table,
             last_timestamp
@@ -172,7 +174,19 @@ class IncrementalMigrator:
                 )
                 progress.__enter__()
 
-            # Transform batch
+            # For tables that need consolidation, group rows by consolidation key
+            # and consolidate before transforming
+            if mysql_table in ("RAWDATACOR", "ELABDATADISP"):
+                # Group batch by consolidation key
+                consolidated_batch = self._consolidate_batch(batch, mysql_table)
+                # Transform consolidated batch
+                transformed = DataTransformer.transform_batch(
+                    mysql_table,
+                    consolidated_batch,
+                    consolidate=False  # Already consolidated above
+                )
+            else:
+                # No consolidation needed for other tables
                 transformed = DataTransformer.transform_batch(
                     mysql_table,
                     batch
@@ -187,6 +201,7 @@ class IncrementalMigrator:
             )
 
             migrated += inserted
+            if progress:
                 progress.update(inserted)
 
         if batch_count == 0:
@@ -267,7 +282,19 @@ class IncrementalMigrator:
                 if not batch:
                     break
 
-                # Transform batch
+                # For tables that need consolidation, group rows by consolidation key
+                # and consolidate before transforming
+                if mysql_table in ("RAWDATACOR", "ELABDATADISP"):
+                    # Group batch by consolidation key
+                    consolidated_batch = self._consolidate_batch(batch, mysql_table)
+                    # Transform consolidated batch
+                    transformed = DataTransformer.transform_batch(
+                        mysql_table,
+                        consolidated_batch,
+                        consolidate=False  # Already consolidated above
+                    )
+                else:
+                    # No consolidation needed for other tables
                     transformed = DataTransformer.transform_batch(
                         mysql_table,
                         batch
@@ -304,6 +331,59 @@ class IncrementalMigrator:
 
         return migrated
 
+    def _consolidate_batch(self, batch: list, mysql_table: str) -> list:
+        """Consolidate batch by grouping rows with same consolidation key.
+
+        Args:
+            batch: List of rows from MySQL
+            mysql_table: Table name (RAWDATACOR or ELABDATADISP)
+
+        Returns:
+            List of rows, already consolidated by consolidation key
+        """
+        if not batch:
+            return batch
+
+        # Group rows by consolidation key
+        groups = {}
+        for row in batch:
+            # Build consolidation key
+            if mysql_table == "ELABDATADISP":
+                key = (
+                    row.get("UnitName"),
+                    row.get("ToolNameID"),
+                    row.get("EventDate"),
+                    row.get("EventTime")
+                )
+            else:  # RAWDATACOR
+                key = (
+                    row.get("UnitName"),
+                    row.get("ToolNameID"),
+                    row.get("EventDate"),
+                    row.get("EventTime")
+                )
+
+            if key not in groups:
+                groups[key] = []
+            groups[key].append(row)
+
+        # Consolidate each group and flatten back to list
+        consolidated = []
+        for key, group_rows in groups.items():
+            if len(group_rows) == 1:
+                # Single row, no consolidation needed
+                consolidated.append(group_rows[0])
+            else:
+                # Multiple rows with same key, consolidate them
+                consolidated_group = DataTransformer.consolidate_elabdatadisp_batch(
+                    group_rows
+                ) if mysql_table == "ELABDATADISP" else DataTransformer.consolidate_rawdatacor_batch(
+                    group_rows
+                )
+                consolidated.extend(consolidated_group)
+
+        return consolidated
+
 
 def run_incremental_migration(
     table: str,