The caller-half of the global case: `g = mk()` into a GLOBAL array
stored only the first word — a ≤24B reg-return landed `MOVQ AX, g(SB)`
(8 of 24 bytes); a >24B sret-return hit the #220 sret-to-symbol gate
which was TY_STRUCT-only and fell through to the same truncation.
≤24B: the local aggregate-receive arm was `off != 0`-only, so a global
array fell to the scalar IDENT store. Add a global ARRAY arm — LEAQ
name(SB), DI then store the full+tail words from AX/DX/CX (an array is
never float-class, so AX/DX/CX is always the transport; no `g+8(SB)`
operand form exists). Mirrors the str/slice global arm.
>24B: add TY_ARRAY to the #220 sret-to-symbol gate (cg_sret_dest_sym /
sretdestnode) — the callee writes the whole array through RDI.
A ≤24B STRUCT global receive can be float-class (X0/X1, not AX/DX/CX),
so it is left at its pre-existing symmetric behaviour — no consumer.
949_aggret_source_run gains global_recv (c → 15) and global_recv_sret
(>24B → 22), both with per-row byte-id.
The N_RETURN aggregate arms gated the return source on N_IDENT ||
N_STRUCTLIT; every other aggregate rvalue (array literal, o.field N_DOT,
a[i] N_INDEX, *p deref) fell through to the scalar-AX default = a silent
8-byte truncation. Both stages emitted byte-IDENTICAL wrong asm, so the
byte-id gate could not catch it (#263 class) — the fix converges on the
runtime oracle.
Mirror the arg-side closure #271 landed: both arms (≤24B @retscr and
>24B sret) now funnel N_ARRLIT through the literal element fill and
N_DOT/N_INDEX/deref through aggarg_srcaddr + the #265/#268 whole-
aggregate copy. Type-agnostic, so struct AND array returns are closed.
A close-by-construction loud-stop (rule 7) guards any future unhandled
aggregate source from reaching the scalar default.
Closes the callee-half of (b)/(c) and the addressable siblings. The
g = mk() global-receive caller-half is commit-2.
949_aggret_source_run pins the class: array-literal / N_DOT / N_INDEX /
deref / named-ident control / >24B-sret-deref / struct-field / struct-
deref, each summing all members (full readback) with per-row byte-id.
