提示词：

对标 LinuxCNC，分阶段完善 Web 版数控系统仿真的 WASM 程序，继续补齐 G/M 代码语法并严格测试。

总结：
按 LinuxCNC read_g/read_m 的模态组规则，补充同一行同模态组 G/M 码冲突检查；新增 G0 G1 与 M3 M4 拒绝用例。已通过 ./test-native.sh 和 ./test-linuxcnc-source-link.sh。

core/tests/cnc_sim_api_smoke.cpp

@@ -3572,6 +3572,25 @@ int main() {
                                        sizeof(duplicate_axis_word_program) - 1) != 0,
                  "expected LinuxCNC to reject multiple X words on one line");
 
+    const char same_modal_group_g_program[] =
+        "G21 G90\n"
+        "F100\n"
+        "G0 G1 X1\n";
+    events.clear();
+    ok &= expect(cnc_sim_parse_program(sim,
+                                       same_modal_group_g_program,
+                                       sizeof(same_modal_group_g_program) - 1) != 0,
+                 "expected LinuxCNC to reject two G codes from the same modal group");
+
+    const char same_modal_group_m_program[] =
+        "G21 G90\n"
+        "M3 M4\n";
+    events.clear();
+    ok &= expect(cnc_sim_parse_program(sim,
+                                       same_modal_group_m_program,
+                                       sizeof(same_modal_group_m_program) - 1) != 0,
+                 "expected LinuxCNC to reject two M codes from the same modal group");
+
     const char scientific_notation_word_program[] =
         "G21 G90\n"
         "F100\n"