wcc/check+wcc_ww/check: reject overlong array literal — frame-smash class (#71)

An array literal with more elements than the declared [N] passed the
per-element accept-if-fits checks in both stages and cgen then stored
every element at its natural offset, writing past the slot: local
frames smashed silently (the repeat form [1,2,3...] into [2]int wrote
at the saved BP), module DATA corrupted neighbours. All four
declaration contexts (local let, module let, def, struct-field
literal) funnel through one choke point per stage — arrlit_init_fits
(check.c) / checkarrlitfits (check.ww) — which now pre-counts the
literal (skipping the ... marker) and rejects count > N naming both
counts.

cstage clet's blanket has_arr_repeat bypass is narrowed to non-array
declared targets: repeat literals into arrays now run the same
overlong + #130 range checks wwstage's checkletassign always ran
(the bypass let [2]u8 = [999...] dodge the range check cstage-only).

checkarrlitfits also recurses into NESTED array-literal elements
(declared elem node N_TARRAY): cstage catches the nested shape
through its typed-literal assignability net, which wwstage's untyped
elements have no analog of — [2][2]int = [[1,2,3],[4,5]] at module
scope silently emitted corrupted DATA (1,2,4,5) and the struct-field
twin likewise. Recursion through the one choke point closes any
depth; a named-alias element type still bypasses — task #16.

alen==0/nil-length stays exempt ([0]/[_] sentinel conflation and
un-inferred [_] in def/struct-field — task #11); a non-INTLIT length
child (def-named [N]) is exempt in wwstage — task #13; under-long
literals keep their current accept (Hare rejects — task #10);
wwstage's overlong accept at assign/call-arg/return position (cstage
already rejects) is task #12; exact-fit bare-int nested cs-reject/
ww-accept divergence is pre-existing — task #17.

Makefile

@@ -394,6 +394,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_append_wide_elem \
 	  $(BIN)/test_delete_elem \
 	  $(BIN)/test_insert_elem \
+	  $(BIN)/test_arrlit_overlong \
 	  $(BIN)/test_placeaddr_store \
 	  $(BIN)/test_tryprop_multisuccess \
 	  $(BIN)/test_append_place \
@@ -1039,6 +1040,17 @@ $(BIN)/test_insert_elem: test/wcc/807_insert_elem.c \
 # cgplaceaddr resolver — runtime rows across widths/signedness/str +
 # compound ops + loud-tail reject rows w/ exact diagnostic text + cs==ww
 # asm byte-id.
+# #71: overlong array literal (more elements than the declared [N]) is
+# a loud checker reject in BOTH stages — local/module/def/struct-field +
+# the repeat-marker form (which used to clobber the saved BP) — plus
+# accept guards (exact-N, repeat-fill, [_] inference) w/ runtime + asm
+# byte-id on both drivers.
+$(BIN)/test_arrlit_overlong: test/wcc/808_arrlit_overlong.c \
+		$(BIN)/ww $(BIN)/w6c $(BIN)/w6c_ww $(BIN)/w6a $(BIN)/w6l \
+		$(BIN)/ww_ww \
+		$(LIB)/libwwrt.a | $(BIN)
+	$(CC) $(CFLAGS) -o $@ $<
+
 $(BIN)/test_placeaddr_store: test/wcc/805_placeaddr_store.c \
 		$(BIN)/ww $(BIN)/w6c $(BIN)/w6c_ww $(BIN)/w6a $(BIN)/w6l \
 		$(BIN)/ww_ww \