Detach non-interactive subprocesses from stdin (#34612)

## What changed

Redirect stdin to null when launching:

- `codex doctor --json` for uploaded diagnostic reports
- Git commands used by `codex doctor`
- ripgrep searches over rollout files
- the Windows sandbox setup refresh helper

This keeps these non-interactive subprocesses from reading Codex's inherited
input stream.

GitOrigin-RevId: 063d191b0b1b849d74b55a7d6ff2f0b3d5212c86

codex-rs/windows-sandbox-rs/src/setup.rs

@@ -345,7 +345,10 @@ fn run_setup_refresh_payload(b64: &str, codex_home: &Path) -> Result<()> {
     };
     // Refresh should never request elevation; ensure verb isn't set and we don't trigger UAC.
     let mut cmd = Command::new(&exe);
-    cmd.arg(b64).stdout(Stdio::null()).stderr(Stdio::null());
+    cmd.arg(b64)
+        .stdin(Stdio::null())
+        .stdout(Stdio::null())
+        .stderr(Stdio::null());
     let cwd = std::env::current_dir().unwrap_or_else(|_| codex_home.to_path_buf());
     log_note(
         &format!(