[AZ-662] [AZ-669] Close batch 19: green test gate via Jetson Docker

Stand up a production-target test runner on jetson-e2e and run the
deferred cargo test --workspace for batch 19.

Infra:
- Dockerfile.test: ubuntu:22.04 + libopencv-dev + libav*-dev +
  libclang-dev + protobuf-compiler + rust 1.82.0 (rustfmt, clippy).
  Sets LIBCLANG_PATH so clang-sys can dlopen libclang under the
  opencv-rust clang-runtime path.
- scripts/jetson-test.sh: rsync source to jetson-e2e, docker build,
  docker run cargo test --workspace --no-fail-fast.

Workspace fix exposed by the gate:
- Cargo.toml: enable opencv "clang-runtime" feature. Without it the
  workspace fails to build because clang-sys is shared between
  opencv-binding-generator and bindgen (via ffmpeg-sys-next) and the
  opencv generator panics with "a `libclang` shared library is not
  loaded on this thread" (opencv-rust GH issue #635).

Batch-19 code bugs exposed by the gate (6 compile errors + 1 algo bug):
- movement_detector::optical_flow: min_max_loc signature (opencv 0.98
  expects Option<&mut f64> / Option<&mut Point>); data_mut() returns
  *mut u8 directly, not Result. RANSAC residual now filters by the
  inlier mask returned by find_homography (matches the docstring; was
  systematically over-reporting motion magnitude on synthetic
  pure-pan input).
- semantic_analyzer::scoring::freshness: same data_mut() fix;
  stddev_f32 now takes &impl core::ToInputArray so it accepts the
  BoxedRef<Mat> that Mat::roi returns in opencv 0.98.

Result: 391 tests passed across 58 binaries, 0 in-scope failures.

Two pre-existing failures in frame_ingest (batch 16-18 scope) are
NOT addressed here and are recorded as leftovers:
- frame_ingest_cuvid_segv: HIGH severity production bug; libavcodec58
  advertises h264_cuvid but libnvcuvid.so.1 is missing at runtime, the
  software fallback never fires, first send_packet SEGVs.
- frame_ingest_publisher_timing_flake: LOW severity; Jetson-specific
  timing budget too tight for ac1_three_consumers_at_rate_lose_no_frames.

Neither blocks batch 20 (movement_detector / semantic_analyzer next).

Co-authored-by: Cursor <cursoragent@cursor.com>

crates/semantic_analyzer/src/internal/scoring/freshness.rs

@@ -53,7 +53,8 @@ fn frame_to_gray_mat(frame: &Frame) -> opencv::Result<Mat> {
             let y_len = (w * h) as usize;
             let mut mat = Mat::new_rows_cols_with_default(h, w, core::CV_8UC1, Scalar::all(0.0))?;
             // SAFETY: freshly allocated continuous Mat; no aliasing.
-            let dst = unsafe { std::slice::from_raw_parts_mut(mat.data_mut()?, y_len) };
+            // `data_mut()` returns `*mut u8` directly in opencv 0.98 (no Result).
+            let dst = unsafe { std::slice::from_raw_parts_mut(mat.data_mut(), y_len) };
             dst.copy_from_slice(&data[..y_len]);
             Ok(mat)
         }
@@ -61,7 +62,7 @@ fn frame_to_gray_mat(frame: &Frame) -> opencv::Result<Mat> {
             let rgb_len = (w * h * 3) as usize;
             let mut rgb =
                 Mat::new_rows_cols_with_default(h, w, core::CV_8UC3, Scalar::all(0.0))?;
-            let dst = unsafe { std::slice::from_raw_parts_mut(rgb.data_mut()?, rgb_len) };
+            let dst = unsafe { std::slice::from_raw_parts_mut(rgb.data_mut(), rgb_len) };
             dst.copy_from_slice(&data[..rgb_len]);
             let mut gray = Mat::default();
             imgproc::cvt_color(&rgb, &mut gray, imgproc::COLOR_RGB2GRAY, 0)?;
@@ -128,7 +129,9 @@ fn variance(mat: &Mat) -> opencv::Result<f64> {
     Ok(std * std)
 }
 
-fn stddev_f32(mat: &Mat) -> opencv::Result<f32> {
+// Accept `&impl ToInputArray` so both `&Mat` and `&BoxedRef<Mat>` (returned
+// by `Mat::roi` in opencv 0.98) can be passed without manual deref.
+fn stddev_f32(mat: &impl core::ToInputArray) -> opencv::Result<f32> {
     let mut mean_mat = Mat::default();
     let mut stddev_mat = Mat::default();
     core::mean_std_dev(mat, &mut mean_mat, &mut stddev_mat, &core::no_array())?;