Fire_heat_flux

Sensible and latent heat flux density released by burning fuel, per Eqs. 4–5 of Mandel et al. (2011). Migrated from WildlandFire.jl@126976f2 src/level_set_fire_spread.jl:295 (`FireHeatFlux` @component). Observed-only: fuel_burn_rate, w_l, h_fuel, M_f are inputs (parameters); phi_h and phi_q are algebraic outputs.