执行 AGENTS align-linuxcnc 加速规则

结论：补强 WASM runtime 可执行探针，依据 LinuxCNC src/emc/rs274ngc/rs274ngc_pre.cc 中程序/子程序路径解析对 wordexp() 的使用，覆盖  形式的环境变量展开。验证通过：./test-linuxcnc-wasm-runtime-link.sh、./test-native.sh、./test-linuxcnc-source-link.sh。

core/wasm_shims/cnc_sim_wasm_runtime_probe_main.cc

@@ -60,6 +60,22 @@ bool wordexp_expands_environment_variables() {
     return ok;
 }
 
+bool wordexp_expands_braced_environment_variables() {
+    setenv("CNC_SIM_WORDEXP_BRACED_PROBE", "linuxcnc-braced-wordexp", 1);
+
+    wordexp_t expanded{};
+    if (wordexp("${CNC_SIM_WORDEXP_BRACED_PROBE}/subroutines", &expanded, 0) != 0) {
+        return false;
+    }
+
+    const bool ok = expanded.we_wordc == 1 &&
+                    expanded.we_wordv &&
+                    expanded.we_wordv[0] &&
+                    std::strcmp(expanded.we_wordv[0], "linuxcnc-braced-wordexp/subroutines") == 0;
+    wordfree(&expanded);
+    return ok;
+}
+
 bool hal_lookup_is_unavailable() {
     if (hal_init("cnc_sim_wasm_runtime_probe") != 1) {
         return false;
@@ -109,6 +125,9 @@ int main() {
     if (!wordexp_expands_environment_variables()) {
         return 6;
     }
+    if (!wordexp_expands_braced_environment_variables()) {
+        return 8;
+    }
     if (!hal_lookup_is_unavailable()) {
         return 7;
     }