Add error logging to Activity Log for researcher failures

- Log errors to Activity Log before re-raising exceptions
- Add A2A request failure logging in research_gateway
- Users can now see WHY research failed in the Activity Log

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

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

src/nodes/research_gateway.py

@@ -218,7 +218,13 @@ async def call_research_service(
     if add_log:
         add_log("researcher", f"Submitting research task for {company} ({ticker})...")
 
-    result = await send_message(message)
+    try:
+        result = await send_message(message)
+    except ResearchGatewayError as e:
+        if add_log:
+            add_log("researcher", f"A2A request failed: {str(e)}")
+        raise
+
     task_id = result.get("task", {}).get("id")
 
     if not task_id:

src/nodes/researcher.py

@@ -132,7 +132,9 @@ def researcher_node(state, workflow_id=None, progress_store=None):
             raise RuntimeError(f"All MCP servers failed for {company}. Check API configurations.")
 
     except Exception as e:
-        print(f"Research failed: {e}")
-        raise RuntimeError(f"Research failed for {company}: {str(e)}")
+        error_msg = str(e)
+        print(f"Research failed: {error_msg}")
+        add_log("researcher", f"ERROR: {error_msg}")
+        raise RuntimeError(f"Research failed for {company}: {error_msg}")
 
     return state