test: migrate 24 residual carriers into the fixture corpus

Audit-driven migrate-and-retire wave (one read-only auditor per
carrier batch, verdicts row-checked through the full corpus gate):
every retired carrier's assertions are now owned by declarative
fixtures or an existing owner. 238 new fixtures land (corpus 1,239 ->
1,477; cells 2,954), covering enum/str/slice/tagged array elements,
inferred-length arrays, global slice/str zero-init and literals,
global array/pointer field reads and stores, struct-literal slice
fields, struct returns, float arithmetic, size/int limits, sort and
log-vstream behavior, place-addressed stores, and append places.
Rejection rows STRENGTHEN the old nonzero-exit checks to required
diagnostic fragments; all byte-id claims fold into the blanket
test-data-byteid sweep (now 1,142 compared, 0 pinned-divergent).
Four carriers were fully redundant with existing fixtures/lang tests
(749, 722, 765, and 771's byteid rows) and retire without new rows.
Native carriers 171 -> 147 (residual 135 -> 111).

test/wcc/data/r698_dot_structlit_ellipsis/case.ww

@@ -0,0 +1,10 @@
+//ww:run
+package main;
+type s = struct { a: i64, b: i32 };
+type box = struct { v: s };
+fn mk() box = { return box { v = s { a = 0i64, b = 0i32 } }; };
+fn main() i32 = {
+    let b: box = mk();
+    b.v = s { a = 5i64, ... };
+    return b.v.b;
+};