Add tuple type recomputation after inlining

Introduce helper functions to recompute the `StaticType` of a tuple node
based on its children's types. This ensures that after inlining, tuples
within the AST have concrete types, rather than unresolved type
variables, even when derived from polymorphic functions.

Also adds tests to verify this behavior for both homogeneous and
heterogeneous tuples.

tests/optimizer.rs

@@ -216,3 +216,36 @@ fn test_slot_reuse_non_overlapping_scopes() {
         dump
     );
 }
+
+// ── Tuple type recomputation after inlining ─────────────────────────────────
+
+#[test]
+fn test_inlined_tuple_has_concrete_type_homogeneous() {
+    // A polymorphic function returning a tuple, called with all-Int args.
+    // After inlining, the tuple type must be concrete (no unresolved TypeVars).
+    let env = Environment::new();
+    let source = r#"(do
+        (def wrap (fn [x y z] [x y z]))
+        (wrap 1 2 3)
+    )"#;
+    let dump = env.dump_ast_compact(source).unwrap();
+    assert!(
+        !dump.contains('?'),
+        "Inlined tuple must not contain unresolved TypeVars. Dump:\n{dump}"
+    );
+}
+
+#[test]
+fn test_inlined_tuple_has_concrete_type_heterogeneous() {
+    // Heterogeneous case: Int + String should produce Tuple([int, str]), not ?0/?1.
+    let env = Environment::new();
+    let source = r#"(do
+        (def wrap (fn [x y] [x y]))
+        (wrap 1 "hello")
+    )"#;
+    let dump = env.dump_ast_compact(source).unwrap();
+    assert!(
+        !dump.contains('?'),
+        "Inlined tuple must not contain unresolved TypeVars. Dump:\n{dump}"
+    );
+}