feat(lang): module NAME uses A, B - a module reaches only the modules it names

A reference from a module that declares uses into a module it does not
name is refused, exported or not, naming the use and the fix. A module
with no uses clause keeps the old rule; a package's module is always
usable; a friend is not held to it; a cycle in the declared graph is
refused; LUDIC_VIS_REPORT=1 lists the violations as uses: lines. Reseed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/modules/valley/base/index.ludic

@@ -0,0 +1,5 @@
+# base/index.ludic - a module with no uses line keeps the old rule: its exports are anyone's
+module base
+export function bait() -> int {
+  return 3
+}