fix: allow lexical import shadowing

test/wcc/data/paramshadowmod/neg_mlet.ww

@@ -1,9 +1,8 @@
-// neg_mlet — Hare tuple destructure `let (shadowmod, x) = pair();`
-// where the first binder shadows the imported module. N_MLET wires
-// check_module_shadow per-binder, so the rule fires at the first
-// name; the second binder `x` is innocuous.
+// Legacy neg_mlet, now a positive tuple-binding case. The selector use before
+// the destructure belongs to the import; afterward shadowmod is the first
+// tuple element. Builds and runs 42 + 1 + 2 = 45.
 
-package paramshadowmod;
+package main;
 
 import shadowmod;
 
@@ -11,7 +10,8 @@ fn pair() (i64, i64) = {
 	return 1i64, 2i64;
 };
 
-export fn main() i32 = {
+fn main() i32 = {
+	let anchor: i32 = shadowmod.say();
 	let (shadowmod, x) = pair();
-	return (shadowmod + x): i32;
+	return anchor + (shadowmod + x): i32;
 };