refactor open_vocab into yolo_onnx and yoloworld_onnx engines

Split the monolithic open_vocab engine into two focused engines:
yolo_onnx (closed-vocabulary, any single-input YOLO ONNX) and
yoloworld_onnx (open-vocabulary YOLO-World with CLIP encoder).
Shared NMS/letterbox/fuse helpers extracted to yolo_helpers.h.
Add export_yolo.py script and separate test binaries for each engine.

CMakeLists.txt

@@ -24,7 +24,8 @@ add_executable(dora_zed
     src/main.cc
     src/zed/camera.cc
     src/engines/zed_native.cc
-    src/engines/open_vocab.cc
+    src/engines/yolo_onnx.cc
+    src/engines/yoloworld_onnx.cc
     ${node_bridge}
 )
 add_dependencies(dora_zed Dora_cxx)
@@ -45,21 +46,40 @@ target_link_libraries(dora_zed dora_node_api_cxx ${ZED_LIBRARIES} ${OpenCV_LIBS}
 
 install(TARGETS dora_zed DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/bin)
 
-# Standalone detector test — no dora, no live camera required
-add_executable(test_open_vocab
-    src/test_open_vocab.cc
-    src/engines/open_vocab.cc
+# Standalone detector tests — no dora, no live camera required
+
+add_executable(test_yolo_onnx
+    src/test_yolo_onnx.cc
+    src/engines/yolo_onnx.cc
 )
-target_include_directories(test_open_vocab PRIVATE
+target_include_directories(test_yolo_onnx PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}/src
     ${ZED_INCLUDE_DIRS}
     ${OpenCV_INCLUDE_DIRS}
     ${CUDAToolkit_INCLUDE_DIRS}
     ${ONNXRUNTIME_INCLUDE_DIRS}
 )
-target_link_libraries(test_open_vocab PRIVATE
+target_link_libraries(test_yolo_onnx PRIVATE
     ${ZED_LIBRARIES}
     ${OpenCV_LIBS}
     ${ONNXRUNTIME_LIBRARIES}
 )
-install(TARGETS test_open_vocab DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/bin)
+install(TARGETS test_yolo_onnx DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/bin)
+
+add_executable(test_yoloworld_onnx
+    src/test_yoloworld_onnx.cc
+    src/engines/yoloworld_onnx.cc
+)
+target_include_directories(test_yoloworld_onnx PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/src
+    ${ZED_INCLUDE_DIRS}
+    ${OpenCV_INCLUDE_DIRS}
+    ${CUDAToolkit_INCLUDE_DIRS}
+    ${ONNXRUNTIME_INCLUDE_DIRS}
+)
+target_link_libraries(test_yoloworld_onnx PRIVATE
+    ${ZED_LIBRARIES}
+    ${OpenCV_LIBS}
+    ${ONNXRUNTIME_LIBRARIES}
+)
+install(TARGETS test_yoloworld_onnx DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/bin)