Epic 105: add camera calibration contracts

[rsasaki0109]

Summary

• add robust pinhole and Kannala-Brandt4 fisheye calibration
• add stereo/hand-eye translation and fixed-camera bundle-adjustment contracts
• add Python bindings, OpenCV correctness receipt, and Criterion workloads

Validation

• cargo test -p spatialrust-camera
• cargo clippy -p spatialrust-camera -- -D warnings -A clippy::manual-div-ceil
• cargo bench -p spatialrust-camera --bench calibration --no-run
• python -m pytest crates/spatialrust-py/tests -q
• python bench/opencv_comparison/run.py --suite calibration