Claude Code: Improve sys.path setup in error_handlers.py - add defensive path verification

- Verify .openclaw exists before adding to sys.path
- Add fallback path resolution for Docker environments
- This ensures brain_minimal imports work correctly on Cain restart

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

error_handlers.py

@@ -17,11 +17,16 @@ from fastapi.responses import JSONResponse
 _openclaw_package_dir = Path(__file__).parent / "openclaw"
 _openclaw_internal_dir = _openclaw_package_dir / ".openclaw"
 
+# Verify paths exist before adding (defensive: helps debug Docker issues)
+if not _openclaw_internal_dir.exists():
+    # Fallback: try .openclaw directly (in case openclaw/ structure differs)
+    _openclaw_internal_dir = Path(__file__).parent / ".openclaw"
+
 # Add openclaw parent dir and .openclaw to sys.path for agents imports
-if str(_openclaw_package_dir) not in sys.path:
-    sys.path.insert(0, str(_openclaw_package_dir))
-if str(_openclaw_internal_dir) not in sys.path:
-    sys.path.insert(0, str(_openclaw_internal_dir))
+for path_dir in [_openclaw_package_dir, _openclaw_internal_dir]:
+    path_str = str(path_dir)
+    if path_str not in sys.path and path_dir.exists():
+        sys.path.insert(0, path_str)
 
 
 async def http_exception_handler(request: Request, exc: HTTPException) -> JSONResponse: