Week 2 release: canonical planar examples and refreshed gallery.
Highlights:
- Added four-bar linkage example.
- Added scotch-yoke example.
- Added driven-pendulum example.
- Added undamped mass-spring energy-conservation example.
- Refreshed gallery generation with seven PNG outputs.
- Made the examples repo buildable as mbsd_examples.
- Pinned CI to the paired mbsd-core v0.2.0 release.