[codex] Load API curated marketplace by auth (#28383)

## Summary
- choose the local OpenAI curated marketplace manifest based on auth:
Codex backend auth gets the existing marketplace, direct provider auth
gets `api_marketplace.json`
- include Bedrock API key auth in the direct-provider API marketplace
path
- safely skip the API marketplace when `api_marketplace.json` is absent

## Validation
- `just fmt`
- `git diff --check origin/main...HEAD`
- CI should run the full validation

## Manual Testing

### - New api marketplace not available for API key sign
1. Safely not display anything from api marketplace
<img width="1161" height="289" alt="Screenshot 2026-06-15 at 21 37 43"
src="https://github.com/user-attachments/assets/a5f16642-8a20-4ac1-a0de-1274a4c7b5b2"
/>

### - New api marketplace for API key sign in
1. Setup api_marketplace.json
```
{
  "name": "openai-curated",
  "interface": {
    "displayName": "Codex official"
  },
  "plugins": [
    {
      "name": "linear",
      "source": {
        "source": "local",
        "path": "./plugins/linear"
      },
      "policy": {
        "installation": "AVAILABLE",
        "authentication": "ON_INSTALL"
      },
      "category": "Productivity"
    }
  ]
}
```

2. Log in with API key, observe that only the defined plugin from
api_marketplace.json is available from "Codex Official" (outside of
local testing marketplaces)
<img width="1167" height="446" alt="Screenshot 2026-06-15 at 21 16 53"
src="https://github.com/user-attachments/assets/7cf61477-d826-4ef6-bc05-0a23ac1c0259"
/>

also checked functionality on codex app

### - SiWC users 
Still uses 'default' marketplace.json and renders all plugins
<img width="1171" height="502" alt="Screenshot 2026-06-15 at 21 40 25"
src="https://github.com/user-attachments/assets/d212ea9b-0aa5-470b-8ea4-450efe65bb2b"
/>

also checked functionality on codex app


## Notes
- `just test -p codex-core-plugins` was started locally before splitting
branches, but I stopped relying on local tests per follow-up and left
final validation to PR CI.

codex-rs/cli/src/marketplace_cmd.rs

@@ -26,6 +26,7 @@ use std::path::PathBuf;
 use crate::plugin_cmd::JsonMarketplaceSource;
 use crate::plugin_cmd::configured_marketplace_snapshot_issues;
 use crate::plugin_cmd::configured_marketplace_sources;
+use crate::plugin_cmd::load_cli_auth_mode;
 
 #[derive(Debug, Parser)]
 #[command(bin_name = "codex plugin marketplace")]
@@ -208,6 +209,7 @@ async fn run_list(overrides: Vec<(String, toml::Value)>, args: ListMarketplaceAr
         .await
         .context("failed to load configuration")?;
     let manager = PluginsManager::new(config.codex_home.to_path_buf());
+    manager.set_auth_mode(load_cli_auth_mode(&config).await);
     let plugins_input = config.plugins_config_input();
     let marketplace_listing = manager
         .discover_marketplaces_for_config(&plugins_input, &[])