test: port 696/697/699 resolver carriers to corpus fixtures

696_modtype_leaf_collision.c -> r696_modtype_leaf_pos (run-exit 26),
  r696_modtype_leaf_neg (staged error; w6c 'no field', w6c_ww
  asserttyped: dot — the old no-wwstage-checkfile comment is stale)
697_samemod_prefer.c -> r697_samemod_prefer (compile)
699_use_promote_alias.c -> r699_usepromote_{type,fn,def,var}
  (run-exit 42 each)

Single-file multi-package form folds the modcollision/samemodprefer/
usepromote data trees into the fixtures; the trees retire with their
carriers. The dir-tree .wwi transport of colliding type decls is owned
by test/byteid/wwi_test.ww. Coverage upgrades: 697 and the 699 rows
gain the wwstage leg the carriers gated or skipped, and all positive
rows enter the blanket test-data-byteid net.

test/wcc/data/r699_usepromote_fn/case.ww

@@ -0,0 +1,16 @@
+//ww:run-exit 42
+// migrated from test/wcc/699_use_promote_alias.c: SK_USE->SK_FN promotion (the original bug) must keep use_alias or `fnmod.flag` fails "unknown type".
+package fnmod;
+export type flag = enum i32 {
+	NONE = 0,
+	A    = 42,
+};
+export fn fnmod() i32 = {
+	return 0i32;
+};
+package main;
+import fnmod;
+fn main() i32 = {
+	let m: fnmod.flag = fnmod.flag.A;
+	return m: i32;
+};