Cement clinker energy input fix

premise v2.4.6

This patch release fixes cement clinker fuel accounting in scenario-transformed databases.

Highlights

• Corrected clinker kiln fuel-efficiency adjustments to account for secondary-fuel energy represented by emissions but
  not listed as burdened technosphere fuel inputs.
• Prevented over-reduction of hard coal inputs when clinker datasets contain multiple hard-coal exchanges by applying
  the energy reduction once to aggregate hard coal, then scaling split suppliers proportionally.
• Updated fossil CO2 changes from the actual applied hard-coal energy change while leaving non-fossil CO2 unchanged
  outside CCS handling.
• Enforced practical clinker fuel-demand floors of 3.1 GJ/t for ordinary clinker production and 3.0 GJ/t for
  efficient dry kiln technologies.
• Added explicit dataset and exchange comments to transformed clinker inventories documenting visible fuel energy,
  inferred hidden secondary-fuel bookkeeping, old/new fuel demand, hard-coal scaling, and CO2 handling.
• Added regression tests for split hard-coal inputs, fuel-demand floors, non-negative hard-coal scaling, and the new
  comment metadata.

Validation

• Focused cement regression tests pass.