[transfix]

Swap from pycvc_gl.camera import ChaseCamera for NativeChaseCamera as ChaseCamera in scripts/examples/grl_snam_austin_drive.py, so this example runs
the SAME follow-camera as C++ instead of the parallel pure-Python implementation
(the unification from libcvc #381 / #391). Matches the grl-snam demo migration
(CVC-Lab/GRL-SNAM#81, CVC-DBG/grl-snam-dbg#82).

Pure drop-in: NativeChaseCamera has the identical constructor and
update(pos, dt) -> (eye, target, up) contract (the example only calls update), and
libcvc's cvcgl_track_parity (C++, 7.1e-15) and test_pycvc_gl_chase_parity (Python)
prove it returns the same pose as the pure-Python ChaseCamera. Behaviour is
unchanged.

NOTE: merge only once a pycvc-gl package that ships NativeChaseCamera (built
against a cvcGL with #381's push-feed: feedTrackTarget/get_pose) is installed —
the currently-installed pycvc_gl extension predates it. Prepared, not merged.

Release gate: met (2026-10-09)

The NOTE above is resolved; this was held only until a released pycvc-gl shipped NativeChaseCamera:

• libcvc #391 (merged 2026-09-21) is an ancestor of v3.5.0; the catalog's latest pycvc-gl-cp312 is 3.5.0+cvc.2.
• The released Linux bundle ships pycvc_gl/camera.py with class NativeChaseCamera, and its _pycvc_gl.so binds every method the shim calls: CameraController_{feedTrackTarget,get_pose,resetTracking,setUpAxis,setMode}.
• Re-checked against today's base that every changed call site still only calls .update(), with up=(0,0,1) and the default widen_tau=0, the regime where parity is proven.
• Parity at these exact constructor args: (34, 13, look_up 2.5) and (55, 42, look_up 3.0). I used the v3.5.0 shim over a local python-VTK pycvc_gl and drove 600 frames: curving, a full stop to hit the min_speed freeze, a reversal, and mixed dt. Max pose difference was 2.8e-14.
• Branch updated from base; the diff is still the one-line import swap per file.
• Sibling CVC-DBG/grl-snam-dbg#82 (the same swap in 3 DBG demos) merged 2026-10-09.
• Note for this example only: it constructs the camera at module top level without app=, so NativeChaseCamera makes its own pycvc.make_app() for the controller's state tree (default path chase.camera). That tree is separate from volrover3's, so the two don't collide. Pass app= later if the camera knobs should be reachable from volrover3's state.