Every section banner dies (103 -> 0) across test/lang, the observer
suites, the C carriers, and the five comment-heavy corpus fixtures;
banner provenance (#N cites, carrier numbers, repair-cluster labels)
folded into headers or adjacent WHY comments. Narration deleted; row
provenance, ref cites, divergence pins, and layout contracts kept
(fwd-ref decl-order guards and bootstrap-gate corpus rationale
restored where the sweep over-cut). Comment-only proven: all 3742
wwbuild workdir .s byte-identical before/after; test-commit and
test-byteid (161 lang + 1399 data, 0 pinned-divergent) green.
Birth test/sep/ (single-file ww observers on test/testenv, run by the
new SEP_WW_TARGETS pattern rule under test-compiler) with
sepbuild_test.ww: the build_one_sep real-chain gate incl. the
bodies==.wwi keystone recompile, the #69 root-without--I contract, the
#70 aggregate-def .wwi prototypes, and the #95 spread-marker
round-trip. Every carrier assertion has a successor row; the C
cleanup-accounting ledgers collapse into testenv.clean.
