Brummel
5b635760b9
Records the schema additions (TypeDef.drop_iterative, serde-skip when false), why heap-stretchy-buffer worklist was chosen over slot-repurposing (not every box has a free ptr-slot to thread through), the mono-typed worklist trade-off (simpler loop body, small cross-type cascade penalty), the four new ABI symbols in runtime/rc.c, and the validation against Decision 10's brief. Validation note: hand-run confirmed the 1M-cell fixture with the annotation exits 0; same fixture without the annotation SIGSEGVs (exit 139). The annotation is load-bearing, not cosmetic. Closes with the dispatch line for 18f (RC validation bench + Boehm retirement decision) and reaffirms the post-18f tidy-iter will be ailang-architect-driven drift cleanup over the whole 18-arc surface.