test: migrate Fam13 misc checker/coercion value tests to @test (#5-C6)

Final fold-2 chunk. The 12 Fam13 single-file value drivers move from
test/wcc/*_run.c into in-language @test row-tables under test/lang/:

- value rows -> test/lang/*_test.ww (12 files)
- reject rows -> runww //ww:error carriers (13, dual-stage non-vacuous)
- nullable abort rows -> runww //ww:run-exit 1 carriers (3)
- 953_globalslice_arg -> _runonly (cs!=ww checker divergence, #28)
- 788 value_not_type_neg + 953_arrlit_slice reject_assign kept as slim
  rc-only .c pins (divergent-diag dual-reject, mutation-gated); 788 #29

Coverage parity verified row-by-row vs each retired driver; advisor-
ratified carve taxonomy; two-round reviewed. Floor ratchet follows.

test/wcc/data/forrange_arr_field_base/case.ww

@@ -0,0 +1,12 @@
+//ww:error "for-range over a non-ident array base unwired (#70)"
+// #70 carrier: for-range over a non-ident ARRAY base (struct field) stays
+// LOUD on both stages until a consumer wires it. Migrated from
+// test/wcc/937_forrange_fieldbase_run.c reject_arr_field row.
+package main;
+type holder = struct { arr: [3]i64, n: i64 };
+export fn main() i32 = {
+	let h: holder = holder { arr = [1, 2, 3], n = 0 };
+	let s: i64 = 0;
+	for (let v .. h.arr) { s += v; };
+	return (s: i32);
+};