test: retire 13 byteid carriers into the corpus blanket

Ten of the thirteen were already fully twinned — their runtime rows
migrated in earlier waves (r56_def_*, r79_*, r78_*, r926_*,
r989_m1union_*) and the carriers survived only for a cstage-vs-wwstage
byte-compare the blanket test-data-byteid comparator owns once the
source is a corpus fixture. The other three needed their remaining
inline sources added first: r756_* (4, alias-chain unwrap),
r844_bid_src (size(u64) untyped-int compare), r989_structframe_* (3,
struct-local frame layout). Every new fixture was verified both-stage:
compile exit 0 twice, .s byte-identical, runtime exit as pinned.

The five ww_ww-driver-leg carriers among them (785/786/789/790/
m1union) follow the 815/940/951 precedent: content identity owned by
their corpus twins, driver-leg identity owned by 989_lib_byteid's
sweep. Byte/artifact partition 24 -> 11; carriers 147 -> 134; corpus
pin 1495/2990; the stale 915 sweep figure in the docs corrected to
the true 1,157 non-error count.

test/wcc/732_def_const_fold.c

@@ -2,10 +2,11 @@
  * 732_def_const_fold — top-level `def` rhs const-fold extended to
  * sibling/imported def references, casts, and arithmetic (PROJECT #88).
  *
- * Predecessor 631_def_neg_global lifted the LITERAL fold (INTLIT/RUNELIT/
- * TRUE/FALSE/NIL + unary +/-/~) into the shared fold_int_literal /
- * foldintliteral helper; it explicitly left N_CAST, sibling-ident, and
- * N_BIN OUT OF SCOPE (see 631's header, "negative-u32-cast"). #88 brings
+ * Predecessor 631_def_neg_global (retired; its rows live as the
+ * r56_def_* corpus fixtures under the blanket byteid sweep) lifted the
+ * LITERAL fold (INTLIT/RUNELIT/TRUE/FALSE/NIL + unary +/-/~) into the
+ * shared fold_int_literal / foldintliteral helper; it explicitly left
+ * N_CAST, sibling-ident, and N_BIN OUT OF SCOPE. #88 brings
  * them in: a Hare-faithful `def SCHAR_MAX = types::I8_MAX;` or
  * `def MASK: i32 = (1 << 7) - 1;` was previously inexpressible — the rhs
  * folded to nothing, no DATA row was emitted, and any reference failed