feat(meep): use reduced Malitson as default SiO2

[vvahidd]

Stacked on #245. Replaces #246.

• Resolve Meep materials from project or gsim MaterialCards and preserve authored constant, Sellmeier, Lorentz, and Drude dispersion.
• Add a lossless two-pole Malitson reduction over 0.4–2.0 µm and use it as the built-in SiO2 fallback; retain the original three-pole Malitson card explicitly.
• Add the lossless Arosa and de la Fuente fused-silica Sellmeier model.
• Reject unsupported material representations instead of silently approximating them.