Thermal_properties

Prescribed thermal conductivity and volumetric heat capacity for urban surface layers (roof, wall, and impervious road) in the urban canopy thermal column. Migrated from UrbanCanopy.jl@9200edd4 src/roof_wall_road_snow_temperatures.jl:245 (`UrbanSurfaceThermalProperties` @component). Implements Section 4.3 of Oleson et al. (2010, CLM Tech Note Ch. 4): for roof, wall, and impervious road layers (i = 1, ..., N_imprvrd) the thermal conductivity λ_surf and the volumetric heat capacity c_surf are specified by the surface dataset (Table 1.3) rather than computed from the layer state. The component takes those prescribed values as parameters and returns them as time-indexed observables — a passthrough/identity wrapper that exposes the surface dataset values on the canonical (λ_surf, c_surf) names the downstream HeatFlux / SurfaceEnergyFlux components consume. Parameterized as observed-only with two algebraic equations: λ_surf and c_surf are state variables; λ_prescribed and c_prescribed are inputs (parameters in standalone form).