Tree-shaking was split across emit-image.ss (the dce-* helpers + record producer)
and build.ss (bld-shake-all + the manifest splice), with the DCE record accessed by
raw (vector-ref r 0..3) in ~10 places and the manifest splice/drop driven by
substring-matching (load "…prelude.ss").
- New host/chez/dce.ss owns the whole DCE concern: a named record API
(dce-rec/-keep?/-fqn/-refs/-str — no more positional vector indexing), the ref
extraction + ref-set constants, dce-blob-records, and dce-shake decomposed into
dce-build-graph / dce-reachable / dce-bail-scan / dce-partition (was one 50-line
bld-shake-all doing five jobs with shared mutable state).
- emit-image.ss keeps only ei-emit-ns-records (it drives the ei-* compiler) and uses
the dce-rec constructor.
- The runtime manifest is now tagged ('prelude/'image/'compile-eval); bld-emit-runtime
dispatches on the tag instead of substring-matching file paths, so the core-splice
and compiler-drop can't silently break on a rename/reorder.
Behaviour-preserving (runtime .ss, no re-mint): build-app shakes identically
(56/460, 8.12MB), make test green, make shakesmoke green (4 git-lib apps
byte-identical, same sizes).