Consolidate isaaclab_visualizers changelog into one fragment

AGENTS.md requires one fragment per touched package. Merge the three
separate fragments (physx-tiled-fix, contamination-fix, shadow-hand-anymal)
into the single canonical mtrepte-golden-image-visualizer-checks.rst and
add the np.frombuffer false-pass fix entry.

Author: matthewtrepte

source/isaaclab_visualizers/changelog.d/mtrepte-golden-image-shadow-hand-anymal.rst

@@ -3,7 +3,39 @@ Added
 
 * Added golden image correctness tests for :class:`~isaaclab_visualizers.kit.KitVisualizer` and
   :class:`~isaaclab_visualizers.newton.NewtonVisualizer` in both viewport and tiled-camera capture
-  modes, covering PhysX and Newton MJWarp physics backends.  Each combination is compared against
-  a committed reference image using a dual-gate (per-pixel L2 norm + SSIM) system adapted from the
-  renderer correctness tests, with per-visualizer pixel-diff and SSIM thresholds tuned to each
-  backend's rendering determinism.
+  modes, covering PhysX and Newton MJWarp physics backends across four scenes (cartpole, shadow
+  hand, AnymalD, and franka cloth).  Each combination is compared against a committed reference
+  image using a dual-gate (per-pixel L2 norm + SSIM) system adapted from the renderer correctness
+  tests, with per-visualizer pixel-diff and SSIM thresholds tuned to each backend's rendering
+  determinism.
+
+Fixed
+^^^^^
+
+* Fixed incomplete tiled camera renders for the PhysX physics backend in golden-image and
+  tiled-camera integration tests.  :class:`~isaaclab_visualizers.newton.NewtonVisualizer` skipped
+  ``_log_camera_sensor_image()`` when the Newton physics state was unavailable (PhysX backend),
+  leaving all owned tiled cameras with zero renderer updates during physics warmup; only env 0
+  rendered correctly.  The capture helper now pumps ``camera_sensor.update()`` for
+  ``_TILED_CAMERA_SENSOR_WARMUP_UPDATES`` iterations before sampling, matching the warmup already
+  applied to Kit viewport and Newton viewer paths.
+
+* Fixed :class:`~isaaclab_visualizers.kit.KitVisualizer` silently skipping tiled camera sensor
+  creation in headless mode even when ``--enable_cameras`` is active.  The camera sensor is now
+  always created when camera rendering is available; only the interactive UI image window is
+  suppressed in headless mode.
+
+* Fixed cross-test contamination in golden image tests when tiled-camera and viewport captures
+  run sequentially in the same process.  Three sources were addressed: (1) the stale
+  :class:`~isaaclab_newton.physics.NewtonManager` shadow model from the tiled stage persisting
+  into the viewport test on the PhysX backend (cleared in the between-test prepare step);
+  (2) CUDA RNG state drift causing the initial cartpole pole angle to differ between isolated
+  and suite runs (seed is now applied immediately before ``env.reset()``); and (3) test ordering
+  in both golden test files reordered to run tiled captures before viewport captures to prevent
+  RTX render-product state from contaminating tiled camera output.
+
+* Fixed false-passing golden image tests caused by ``np.frombuffer`` returning a read-only view
+  of the annotator's internal buffer rather than an independent snapshot.  When Replicator reuses
+  the same buffer in place, both the start-frame and end-frame captures reflected the same
+  (current) buffer contents, producing zero pixel differences.  The frame capture helper now calls
+  ``.copy()`` to take an independent snapshot at capture time.