fix: CRITICAL - Don't prematurely yield incomplete groups at batch boundaries

Bug: When batch limit was reached (len(rows) >= limit), code was yielding the
current_group immediately, even if it was incomplete. This caused groups that
spanned multiple batches to be split.

Example:
- First batch contains UnitA nodes 1-11 with same consolidation key
- Code yields them as complete group before seeing nodes 12-22 in next batch
- Next batch starts with different key, so incomplete group is never merged
- Result: 11 separate rows instead of 1 consolidated row

Root cause: Not checking if the group might continue in the next batch

Fix: Before yielding at batch boundary, check if the LAST row in current batch
has the SAME consolidation key as the current_group:
- If YES (last_row_key == current_key): DON'T yield yet, keep buffering
- If NO (last_row_key != current_key): Yield, group is definitely complete

This ensures groups that span batch boundaries are kept together and fully
consolidated.

🤖 Generated with Claude Code

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

src/connectors/mysql_connector.py

@@ -308,10 +308,25 @@ class MySQLConnector:
                                 yield current_group
                             return
                         else:
-                            # More rows might exist - yield the last group only if key changed
-                            # If not, it will be continued/merged in next iteration
-                            if current_group:
-                                yield current_group
+                            # More rows might exist after this batch
+                            # Check if the last row in this batch has same key as current_group
+                            # If yes, DON'T yield yet - the group might continue in next batch
+                            # If no, yield because we know the group is complete
+                            if rows:
+                                last_row = rows[-1]
+                                last_row_key = (
+                                    last_row.get("UnitName"),
+                                    last_row.get("ToolNameID"),
+                                    last_row.get("EventDate"),
+                                    last_row.get("EventTime")
+                                )
+
+                                # If last row has different key than current group, current group is complete
+                                if last_row_key != current_key and current_group:
+                                    yield current_group
+                                    current_group = []
+                                    current_key = None
+                                # else: same key as current_group, so continue in next iteration
 
                         # Update last_key for next iteration
                         if current_key: