Claude Code: Add defensive brain interface check - verify get_brain exists before calling

This prevents AttributeError if brain_minimal module is loaded but incomplete.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

error_handlers.py

@@ -159,6 +159,10 @@ def handle_brain_response(message: str) -> str:
         import openclaw
         from agents import brain_minimal
 
+        # Verify brain has required method before calling
+        if not hasattr(brain_minimal, 'get_brain'):
+            return "Brain interface error: get_brain method not found"
+
         brain = brain_minimal.get_brain(agent_name="cain", legacy_mode=True)
         result = brain._conversation_process(message)