0.74.0

v0.74.0

Auto-Register detects built scenes instead of asking, and drops the options
that could not change the result. The heading prior is now gated on every
selected scan having a recorded pose — sending it unconditionally put the
correct answer outside the yaw search space for unposed scans.

The RIEGL reader image updates itself when it falls behind, rather than
surfacing a stale-image error behind a button hidden precisely because an
image existed.

CI gains a GPU parity workflow, validated on real hardware (Tesla T4): the
CUDA ray-tracing path is exercised by the CPU-derived scan expectations, so a
CPU/GPU divergence fails the build.