test(c-lsp): regression for #220 (C++ CALLS attributed to function)

#220: C++ CALLS edges originated from the Module node instead of the
enclosing Function, breaking function-level trace_path. The cross-LSP
resolver now sets caller_qn = enclosing_func_qn; the test asserts a call
(doWork→helper) is attributed to doWork, not the module.

Closes #220.

tests/test_c_lsp.c

@@ -583,6 +583,22 @@ TEST(clsp_nocrash_template_function_multi_param_nested_call) {
     PASS();
 }
 
+/* Issue #220: C++ CALLS edges were attributed to the Module (file) node
+ * instead of the enclosing Function/Method, breaking function-level
+ * trace_path. The resolved call's caller_qn must be the enclosing function. */
+TEST(clsp_calls_attributed_to_function_issue220) {
+    CBMFileResult *r = extract_cpp("void helper() {}\n"
+                                   "void doWork() {\n"
+                                   "    helper();\n"
+                                   "}\n");
+    ASSERT_NOT_NULL(r);
+    int idx = find_resolved(r, "doWork", "helper");
+    ASSERT_GTE(idx, 0);
+    ASSERT_NOT_NULL(strstr(r->resolved_calls.items[idx].caller_qn, "doWork"));
+    cbm_free_result(r);
+    PASS();
+}
+
 /* Issue #355: indexing segfaulted while extracting a heavily-macro'd xxhash
  * C header (`dhw/xx_hash.h`). The reporter's exact file isn't available, so
  * this drives the vendored xxhash.h (~7.5k lines, same macro-dense family)
@@ -15196,6 +15212,7 @@ SUITE(c_lsp) {
     RUN_TEST(clsp_nocrash_template_expression);
     RUN_TEST(clsp_nocrash_template_extra_call_args);
     RUN_TEST(clsp_nocrash_template_function_multi_param_nested_call);
+    RUN_TEST(clsp_calls_attributed_to_function_issue220);
     RUN_TEST(clsp_nocrash_issue355_xxhash_header);
     RUN_TEST(clsp_nocrash_issue312_default_template_auto_param);
     RUN_TEST(clsp_nocrash_lambda);