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.

tests/unit/utils/claudecode-env-stripping.test.ts

@@ -266,6 +266,7 @@ describe('CLAUDECODE environment stripping', () => {
     expect(spawnCalls.length).toBeGreaterThan(0);
     const env = spawnCalls[0].options?.env as NodeJS.ProcessEnv;
     expect(Object.keys(env).map((k) => k.toUpperCase())).not.toContain('CLAUDECODE');
+    expect(spawnCalls[0].options?.shell).toBe('cmd.exe');
   });
 
   it('execClaude sets DISABLE_AUTOUPDATER=1 when preferences.auto_update is false', () => {