Bug: J/kg auto-simplifies to Gy (Gray) in non-radiation contexts

[parneetsingh022]

When composing units that algebraically reduce to J/kg (e.g., Pa / (J/(kg·K)) in gas density calculations), the unit simplifier replaces J/kg with Gy (Gray), the SI unit for absorbed radiation dose.
This is dimensionally correct (1 Gy = 1 J kg⁻¹) but semantically misleading outside radiological applications.

Example:

p  = 101325 * u.Pa
R  = 287.05 * u.J / (u.kg * u.K)
T  = 20 * u.degC
dT = T - (0 * u.degC)
rho = p / (R * dT)
print(rho.unit.name)
# -> 'Pa/kGy'   # semantically odd, though dimensionally correct

Expected:

Either 'kg/m³' or 'Pa/(J/kg)' — not 'Gy'

Impact

This affects thermodynamic and mechanical contexts (e.g., gas laws, energy density, specific heat, etc.) where J/kg should not be expressed as Gy.
It doesn’t break dimensional correctness but causes confusing unit labels in outputs and logs.