wcc/ww: match-as-expression unifies arm yields (coarse-family gate)

exprtype N_MATCH took the first arm's yield type without walking the
rest — int-vs-str arms silently produced garbage downstream. Walk all
arms: typeeq-equal accepts; a definite coarse-family mismatch
(num/str/bool via the new yieldclass classifier, unknown classes stay
lenient) rejects. Same-family non-assignable pairs remain lenient —
the documented precision residual is task #52 (needs tinfo-level
type_assignable). The wave's table-driven reject test lands here:
989_catA_f2_reject, 19 rows x 2 stages, each member pre-fix-red-proven.

Makefile

@@ -248,6 +248,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_arr_cap_reject \
 	  $(BIN)/test_tagged_subset_reject \
 	  $(BIN)/test_callarg_typecheck \
+	  $(BIN)/test_catA_f2_reject \
 	  $(BIN)/test_idxarg_run \
 	  $(BIN)/test_chainidx_run \
 	  $(BIN)/test_tupfieldsize_run \
@@ -648,6 +649,17 @@ $(BIN)/test_callarg_typecheck: test/wcc/989_callarg_typecheck.c \
 		$(LIB)/libwwrt.a | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<
 
+# 989_catA_f2_reject drives the #38/F2 checker-reject wave (review items
+# #2/#6/#7/#10/#39): each REJECT row must FAIL to build on BOTH driver
+# twins, each control must build+run. Needs the full cstage + wwstage tool
+# sets plus libwwrt for the link.
+$(BIN)/test_catA_f2_reject: test/wcc/989_catA_f2_reject.c \
+		$(BIN)/ww $(BIN)/ww_ww \
+		$(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
+		$(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
+		$(LIB)/libwwrt.a | $(BIN)
+	$(CC) $(CFLAGS) -o $@ $<
+
 # 989_idxarg_run (F7-c2, #45/#46): an indexed slice/str element passed as
 # a call arg must push its full multi-word header. Builds+runs each fixture
 # on BOTH the cstage `ww` and wwstage `ww_ww` drivers (rule-10), so it needs