d_params and the block wall/channel constants are per-module runtime
globals, immutable per stepper instance but not visible to the compiler.
Note that dense and blocked slot roots carry the wall slot as macros vs
d_block_wall respectively.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Describes current module/global, table, control and per-step state
ownership for Simulation, PeriodicBlockStepper and FixedPatchStepper,
and the window vs level-wide frame of single vs multi-rectangle levels.
No code change.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>