remove detection from the node

dora-zed publishes camera data only. The two engines under src/engines/, the
objects output, the ZED_ENGINE/ZED_DETECTION_*/ZED_ONNX_* variables and the
ZED_PC_MODE=ROI crop are gone, along with the standalone engine test and the
model export script.

This drops the unconditional ONNX Runtime requirement from CMakeLists, the
Dockerfile and the install scripts, so the node now configures on a machine
with no ONNX Runtime — which is what blocked the Jetson build, since there is
no official ARM64 GPU binary.

zed_native is dropped rather than kept: it is bound to the live camera handle
and cannot run in a node that receives images over a dataflow. The removed
code remains reachable at tag v0.1.0.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y7g2cBJ5e3r15ZbJ9WZn8c

AGENTS.md

@@ -4,7 +4,9 @@ This file provides guidance to AI coding assistants when working with code in th
 
 ## What this is
 
-A dora-rs C++ node that interfaces with ZED stereo cameras. On each tick it grabs a frame, runs object detection, and publishes four outputs over the dora dataflow: a BGR image, an XYZRGBA point cloud, camera intrinsics, and detected objects with 3D positions. Camera management lives in `src/zed/`, detection engines in `src/engines/`, and the dora event loop in `src/main.cc`.
+A dora-rs C++ node that interfaces with ZED stereo cameras. On each tick it grabs a frame and publishes it over the dora dataflow: a BGR image, an XYZRGBA point cloud and camera intrinsics. Camera management lives in `src/zed/` and the dora event loop in `src/main.cc`.
+
+The node is a camera source only. It ran inference in-process through `v0.1.0`, under `src/engines/`; that was removed so the node has no inference dependency and builds on any platform the ZED SDK supports. The removed code remains reachable at tag `v0.1.0`.
 
 ## Build
 
@@ -16,7 +18,7 @@ The binary is installed to `bin/dora_zed` relative to the repo root. The script
 the dataflow's `build:` command: dora 1.0 executes build commands directly rather than
 through a shell, so `cd`, `&&` and command substitution do not work there.
 
-**Requirements:** dora 1.0+ (verified with `dora-cli 1.0.1`), CMake 3.21+, ZED SDK 5.x (at `/usr/local/zed`), CUDA Toolkit, ONNX Runtime 1.20+ (system install), Rust stable toolchain (for dora-rs C++ bindings).
+**Requirements:** dora 1.0+ (verified with `dora-cli 1.0.1`), CMake 3.21+, ZED SDK 5.x (at `/usr/local/zed`), CUDA Toolkit, Rust stable toolchain (for dora-rs C++ bindings).
 
 The first build clones dora-rs from GitHub and compiles `dora-node-api-cxx` via Cargo. This takes a while. Subsequent builds are incremental. If `DORA_ROOT_DIR` is set to a local dora checkout, it builds against that instead.
 
@@ -29,30 +31,23 @@ dora up
 dora start dataflow.yml
 ```
 
-Camera and detection behavior is configured entirely through environment variables (see README.md for the full list: `ZED_RESOLUTION`, `ZED_FPS`, `ZED_DEPTH_MODE`, `ZED_DETECTION_MODEL`, etc.).
+Camera behavior is configured entirely through environment variables (see README.md for the full list: `ZED_RESOLUTION`, `ZED_FPS`, `ZED_DEPTH_MODE`, etc.).
 
 ## Architecture
 
 - **`src/util/env.h`** — Shared inline env-variable parsing helpers (`get_env_int`, `get_env_str`, `get_env_bool`, `get_env_float`).
 - **`src/zed/camera.h`** — `zed::Config`, `zed::Calibration`, and `zed::Camera` class. Camera wraps the ZED SDK lifecycle: open (with retry loop), warmup, grab (image + point cloud), calibration, and close. Exposes `handle()` for engine access.
 - **`src/zed/camera.cc`** — Implementation. SDK enum parsers live in an anonymous namespace.
-- **`src/engines/engine.h`** — `engines::DetectedObject` struct and `engines::Engine` abstract base class (`enable`, `detect`, `objects`, `label_names`).
-- **`src/engines/zed_native.h/cc`** — `engines::ZedNative`: wraps ZED SDK's TensorRT-optimized object detection module.
-- **`src/engines/yolo_helpers.h`** — Header-only shared helpers used by the ONNX engine: `RawDetection`, `nms()`, `letterbox()`, `fuse_bbox()`, `backproject()`. Lives in `engines::detail` namespace.
-- **`src/engines/yolo_onnx.h/cc`** — `engines::YoloOnnx` / `YoloOnnxConfig`: closed-vocabulary detection for any single-input YOLO ONNX model (YOLOv8, YOLOv11, YOLOv5, etc.). Auto-detects output layout (`NC_FIRST` / `NC_LAST` / `NC_LAST_OBJ`) from tensor shape; override with `ZED_ONNX_OUTPUT_FORMAT`. Labels loaded from `ZED_ONNX_LABELS` or `ZED_ONNX_LABELS_FILE`.
-- **`src/main.cc`** — Dora event loop. Selects engine via `ZED_ENGINE` env var (`yolo_onnx`/`onnx` or `native`), holds a `std::unique_ptr<engines::Engine>`. Parses `ZED_PC_MODE` (`FULL`/`HALF`/`ROI`) once before the loop. On any input event (intended to be driven by a tick timer; the id is not inspected): calls `camera.grab()` and `detector->detect()`, then sends `image_bgr`, `point_cloud`, `camera_info`, and `objects` outputs. Point cloud output varies by mode: `FULL` sends the raw `sl::Mat` pointer (no copy); `HALF` downsamples by 2 in each dimension; `ROI` emits only valid points within detected bounding boxes as a flat `[N, 4]` array. Handles reconnection on grab failure.
+- **`src/main.cc`** — Dora event loop. Parses `ZED_PC_MODE` (`FULL`/`HALF`) once before the loop. On any input event (intended to be driven by a tick timer; the id is not inspected): calls `camera.grab()`, then sends `image_bgr`, `point_cloud` and `camera_info`. Point cloud output varies by mode: `FULL` sends the raw `sl::Mat` pointer (no copy); `HALF` downsamples by 2 in each dimension. Handles reconnection on grab failure.
 - **`DoraTargets.cmake`** — Handles building or fetching dora-rs and generating the CXX bridge files. Two paths: local (`DORA_ROOT_DIR`) or git clone. Produces `dora_node_api_cxx` library and the `node_bridge.cc` glue.
 - **`scripts/build.sh`** — Configure/compile/install in one shell-free-callable step. Referenced by `dataflow.yml`, the `Dockerfile` and the README.
 - **`dataflow.yml`** — Example dora dataflow definition using the `git:` source format, pinned with `tag:` — dora 1.0 pins a source with the mutually exclusive `tag:`, `rev:` or `branch:`.
-- **`Dockerfile`** — Ubuntu 24.04 x86-64 build environment (CUDA 12.8, ZED SDK 5.2, ONNX Runtime, Rust). No ARM64/Jetson image; build natively there. No camera needed; run the compile with `--gpus all`. Sets `NVIDIA_DRIVER_CAPABILITIES=compute,utility,video` — the `video` capability is what makes the container runtime mount NVDEC/NVENC, which `libsl_zed.so` links against. ONNX Runtime's CMake package files are relocated to `/usr/local/lib/cmake` because Ubuntu's multiarch CMake does not search `lib64`. Rust lives at `/usr/local/{rustup,cargo}` rather than `/root` so the build can run as the invoking user. `docker build -t dora-zed-build . && docker run --rm --gpus all --user "$(id -u):$(id -g)" -v "$PWD:/src" -v dora-zed-cargo:/usr/local/cargo/registry dora-zed-build`.
-- **`scripts/export_yolo.py`** — PEP 723 uv script. Exports a standard YOLOv11 model to ONNX for closed-vocabulary detection. Run: `uv run scripts/export_yolo.py --model n --output-dir models/`.
-- **`src/test_yolo_onnx.cc`** — Standalone C++ test binary (`bin/test_yolo_onnx`). Exercises `YoloOnnx` with an image (default `test/assets/yolo.png`). No dora and no live camera required. Uses the same env vars as the main binary. Saves an annotated result image alongside the input.
+- **`Dockerfile`** — Ubuntu 24.04 x86-64 build environment (CUDA 12.8, ZED SDK 5.2, Rust). No ARM64/Jetson image; build natively there. No camera needed; run the compile with `--gpus all`. Sets `NVIDIA_DRIVER_CAPABILITIES=compute,utility,video` — the `video` capability is what makes the container runtime mount NVDEC/NVENC, which `libsl_zed.so` links against. Rust lives at `/usr/local/{rustup,cargo}` rather than `/root` so the build can run as the invoking user. `docker build -t dora-zed-build . && docker run --rm --gpus all --user "$(id -u):$(id -g)" -v "$PWD:/src" -v dora-zed-cargo:/usr/local/cargo/registry dora-zed-build`.
 
 ## Key APIs
 
 - **dora C++ API** (`<dora-node-api.h>`): `init_dora_node()`, `dora_node.events->next()`, `event_type()`, `send_output_with_metadata()`, `new_metadata()`.
-- **ZED SDK** (`<sl/Camera.hpp>`): `sl::Camera`, `sl::InitParameters`, `sl::RuntimeParameters`, `sl::Mat`, `sl::ObjectDetectionParameters`, `sl::Objects`.
-- **ONNX Runtime** (`<onnxruntime_cxx_api.h>`): `Ort::Env`, `Ort::Session`, `Ort::SessionOptions`, `Ort::Value`. Used by the `yolo_onnx` engine.
+- **ZED SDK** (`<sl/Camera.hpp>`): `sl::Camera`, `sl::InitParameters`, `sl::RuntimeParameters`, `sl::Mat`.
 - Output data is sent as raw byte slices (`rust::Slice<const uint8_t>`) with typed metadata (shape, dtype, encoding).
 
 ## Tools