compatibility with latest stk & stko versions

[joshkamm]

• remove version cap on stk in pyproject.toml
• uv pip upgrade all packages in codespace
• try running pytest again
• debug stk changes
  • figure out where stk.molecular.topology_graphs.Edge moved
  • ask at stk workshop about python versions and what has changed
  • ask about where to get stk.molecular.topology_graphs.metal_complex.vertices imports from in new stk versions
• remove version cap on stko