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/r697_samemod_prefer/case.ww

@@ -0,0 +1,22 @@
+//ww:compile
+// migrated from test/wcc/697_samemod_prefer.c: bare-leaf `read` binds same-module first; compile-only (unmangled TEXT read labels still collapse in the linker).
+package mod1;
+export fn read(x: i32) i32 = {
+	return x + 100i32;
+};
+export fn caller() i32 = {
+	return read(1i32);
+};
+package mod2;
+export fn read(x: str) i32 = {
+	return x.len + 200i32;
+};
+export fn caller() i32 = {
+	return read("ok");
+};
+package main;
+import mod1;
+import mod2;
+fn main() i32 = {
+	return 0i32;
+};