fix(targets): use cmd.exe for escaped Windows wrapper launches

Align Windows .cmd/.bat launch behavior with the Codex detector shell contract.

This keeps escaped -c overrides intact through wrapper execution.

Adds regression coverage for the Codex runtime path and the shared Windows shell launch path.

src/utils/shell-executor.ts

@@ -107,6 +107,16 @@ export function escapeShellArg(arg: string): string {
   }
 }
 
+/**
+ * Return the Windows shell that matches escapeShellArg() quoting semantics.
+ *
+ * `shell: true` is not strict enough for npm `.cmd` wrappers because Node may
+ * route through a different quoting path than the one escapeShellArg() expects.
+ */
+export function getWindowsEscapedCommandShell(): string {
+  return 'cmd.exe';
+}
+
 /**
  * Execute Claude CLI with unified spawn logic
  */
@@ -182,7 +192,7 @@ export function execClaude(
     child = spawn(cmdString, {
       stdio: 'inherit',
       windowsHide: true,
-      shell: true,
+      shell: getWindowsEscapedCommandShell(),
       env,
     });
   } else {