Support ChatGPT-branded Desktop app builds (#33901)

## Why

The Desktop app can use Codex or ChatGPT branding while retaining stable platform identities. CLI discovery and TUI handoff should not depend on a single display name or hardcoded executable path.

## What changed

- On macOS, search for both `ChatGPT.app` and `Codex.app`, and accept only bundles with the `com.openai.codex` identifier.
- On Windows, detect installs by their package app ID and resolve the `codex` protocol executable from the AppX manifest before handing off a TUI session.
- Use “Desktop app” consistently in CLI and TUI user-facing text.

## Testing

Add coverage for selecting a ChatGPT-named Codex bundle and rejecting the classic ChatGPT bundle.

GitOrigin-RevId: b84a56eb6e960712152e1a9b023ab530ec9a354a

codex-rs/cli/src/main.rs

@@ -150,7 +150,7 @@ enum Subcommand {
     /// [experimental] Manage the app-server daemon with remote control enabled.
     RemoteControl(RemoteControlCommand),
 
-    /// Launch the Codex desktop app (opens the app installer if missing).
+    /// Launch the Desktop app (opens the app installer if missing).
     #[cfg(any(target_os = "macos", target_os = "windows"))]
     App(app_cmd::AppCommand),