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.
Three more value-observable behavior families ported from the C corpus
to in-language @test, routed by the ratified observability rule (value
-> test/lang @test; process-outcome stays in runww). Additive: the .c
sources keep running in $(TESTS), so no byte-id coverage is removed --
de-dup is deferred to fold 6 (task #12).
906_callret_unsigned_arith -> callret_unsigned_test: call-result
unsigned opcode select keyed by callee return type (#168, the N_CALL
twin of gunsigned's module-global #134); operands flow through real
calls so the return-type arm is exercised, not N_IDENT.
912_sar_shr -> sar_shr_test: signed >> / >>= must emit SAR not SHR
(#136); asserts the i64/i32 value directly, dropping the C 8-bit
exit-code encoding.
793_widen_pad_zero -> widen_pad_test: widening a narrow value into a
wider tagged slot zeroes the high pad words (#227).
