fix: allow lexical import shadowing

test/wcc/data/paramshadowmod/neg_let.ww

@@ -1,12 +1,12 @@
-// neg_let — local `let shadowmod: i32 = ...` shadows the imported
-// module from inside a fn body. Same rule fires for nested-scope
-// let binds, not just params.
+// Legacy neg_let, now a positive declaration-point case. The initializer
+// resolves shadowmod.say through the file-scope import; after the declaration
+// shadowmod denotes the closer i32 binding. Builds and runs 42.
 
-package paramshadowmod;
+package main;
 
 import shadowmod;
 
-export fn main() i32 = {
-	let shadowmod: i32 = 0i32;
+fn main() i32 = {
+	let shadowmod: i32 = shadowmod.say();
 	return shadowmod;
 };