Summary

Add dtype coverage (float32 and float64) to selected mixed-topology mesh tests.

Changes

• Parametrized:

  • test_create_mixed_mesh
  • test_mixed_topology_mesh

• Updated:

  • Geometry arrays to use dtype
  • coordinate_element(..., dtype=dtype)

• Kept:

  • Topology/index arrays as int64 (unchanged)

Rationale

• These tests operate at the mesh/geometry level and are naturally dtype-agnostic, making them suitable for dtype parametrization.
• FEM-level tests (e.g., dofmap tests) were explored but not included due to current limitations:
  Basix UFL elements default to float64, leading to dtype mismatches when using float32.