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/r806ap_spread_dup_copy/case.ww

@@ -0,0 +1,31 @@
+//ww:run-exit 139
+package main;
+type capture = struct {
+	content: str,
+	start: size,
+	start_bytesize: size,
+	end: size,
+	end_bytesize: size,
+};
+type thr = struct { pc: size, caps: []capture };
+export fn main() i32 = {
+	let c0: []capture = [];
+	append(c0, capture { content = "x", start = 3: size, start_bytesize = 3: size, end = 8: size, end_bytesize = 8: size });
+	append(c0, capture { content = "yz", start = 5: size, start_bytesize = 5: size, end = 9: size, end_bytesize = 9: size });
+	let ts: []thr = [];
+	append(ts, thr { pc = 0: size, caps = c0 });
+	let tsp = &ts;
+	let dup: []capture = [];
+	append(dup, (*tsp)[0].caps...);
+	if (len(dup) != 2) { return 1; };
+	if (len(dup[1].content) != 2 || dup[1].content[0] != 'y') { return 2; };
+	let res: []capture = [];
+	append(res, ts[0].caps...);
+	if (len(res) != 2) { return 3; };
+	if (res[0].end != 8 || res[1].start != 5) { return 4; };
+	dup[0].start = 100: size;
+	if (ts[0].caps[0].start != 3) { return 5; };
+	let acc = dup[0].start + dup[1].end + res[0].start + res[1].end_bytesize
+		+ ts[0].caps[0].end + (len(dup): size) * 5;
+	return acc: i32;
+};