Drop unused normal-pass colour-target blend and mask state from pipeline keys.
Normalize historical prewarm rows and deduplicate their parsed keys before
compilation, preserving merged passes' logical target state.
Include production-path GPU regression coverage and the reference/game notes.
Validated on the latest main: Wonder host build, key serialization tests,
48 pending-pipeline checks, 48 archive checks, 158 prewarm GPU checks across
MTLDevice and Metal 4, and documentation checks. The regression fails on the
original base and detects wrong pixels if the merged-pass guard is removed.
Co-authored-by: Aleksandr Svidchenkov <a.svidchenkov@gmail.com>
