Read REVIEW_COMMON.md (repo root) first - its contract binds this checklist. Architecture
doc: CLAUDE.md.
Removing or weakening REVIEW.das's check that no two git-tracked .das files declare the
same shared module name is a defect.
A TOLERATED_SHARED_TWINS row's why names what keeps every process from compiling two of
its name's files; a why that names nothing, or that a build or test run contradicts, is a
defect. The first file a process compiles that declares module X shared becomes that
process's module X, and every later file declaring or requiring X in the same process gets
that module - so any process compiling both gives the second file the first's module.