Epic 107: add robust visual and RGB-D odometry

[rsasaki0109]

Summary

• add deterministic grid feature selection and forward/backward LK validation
• add scale-explicit monocular and metric RGB-D odometry
• bridge vision estimates into stamped mapping motion behind an additive feature
• expose RGB-D odometry to Python and compare against OpenCV solvePnPRansac

Validation

• cargo test -p spatialrust-vision --features full
• cargo test -p spatialrust-mapping --features vision-odometry
• cargo clippy ... --no-deps -- -D warnings (vision + mapping)
• cargo bench -p spatialrust-vision --features odometry --bench odometry --no-run
• pytest crates/spatialrust-py/tests
• OpenCV odometry comparison receipt: pass
• cargo test -p spatialrust-platform