Add null checks for partial metrics and research result

- research_gateway.py: Skip None/invalid metrics in partial_metrics array
- researcher.py: Validate result is a valid dict before processing

Fixes: 'NoneType' object has no attribute 'get' error

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/nodes/research_gateway.py

@@ -135,16 +135,20 @@ async def wait_for_completion(
 
         # Emit partial metrics during WORKING status
         if status == "working" and progress_callback:
-            partial_metrics = task.get("partial_metrics", [])
+            partial_metrics = task.get("partial_metrics", []) or []
             for metric in partial_metrics:
+                # Skip None or invalid metrics
+                if not metric or not isinstance(metric, dict):
+                    continue
                 # Create unique key to avoid duplicate emissions
-                metric_key = f"{metric.get('source')}:{metric.get('metric')}:{metric.get('value')}"
+                source = metric.get("source")
+                metric_name = metric.get("metric")
+                value = metric.get("value")
+                if not source or not metric_name:
+                    continue
+                metric_key = f"{source}:{metric_name}:{value}"
                 if metric_key not in emitted_metrics:
-                    progress_callback(
-                        metric.get("source"),
-                        metric.get("metric"),
-                        metric.get("value")
-                    )
+                    progress_callback(source, metric_name, value)
                     emitted_metrics.add(metric_key)
 
         if status == "completed":

src/nodes/researcher.py

@@ -91,6 +91,11 @@ def researcher_node(state, workflow_id=None, progress_store=None):
             progress_callback=progress_callback,
             add_log=add_log
         ))
+
+        # Validate result
+        if not result or not isinstance(result, dict):
+            raise RuntimeError(f"Research Service returned invalid data for {company}")
+
         state["data_source"] = "a2a"
         # Note: Metrics are streamed via partial_metrics during A2A polling