docs: document both Codex install paths (curated marketplace + ChatGPT /plugins) (#102)

The Codex row showed a bare 'codex plugin add crowdstrike-falcon-foundry' marked (pending), which the CLI rejects — it wants a plugin@marketplace source. OpenAI has since synced the listing into the curated CLI marketplace, so the primary command is now the qualified source.

Codex has two install paths depending on auth mode: API-key and Amazon Bedrock sessions load the curated marketplace (openai-api-curated) and use the command in the table; ChatGPT-authenticated sessions do not load that marketplace and install via /plugins → search crowdstrike instead. Document both so neither audience is left without a working path.

Verified: codex plugin list shows crowdstrike-falcon-foundry@openai-api-curated resolving from the CrowdStrike/foundry-skills repo; the ChatGPT /plugins search path is confirmed by OpenAI and a ChatGPT-authenticated user.

Author: mraible

README.md

@@ -21,11 +21,14 @@ AI coding assistant skills for building [CrowdStrike Falcon Foundry](https://www
 | Assistant | Command | Marketplace |
 |-----------|---------|-------------|
 | Claude Code | `/plugin install crowdstrike-falcon-foundry` | [Anthropic](https://claude.com/plugins/crowdstrike-falcon-foundry) |
-| Codex | `codex plugin add crowdstrike-falcon-foundry` | [OpenAI](https://chatgpt.com/plugins) (pending) |
+| Codex | `codex plugin add crowdstrike-falcon-foundry@openai-api-curated` | [OpenAI](https://chatgpt.com/plugins) |
 | Copilot CLI | `copilot plugin install CrowdStrike/foundry-skills` | [GitHub](https://awesome-copilot.github.com/plugin/crowdstrike-falcon-foundry/) |
 | Cursor | `/plugins` (CLI) or `/add-plugin crowdstrike-falcon-foundry` (IDE) | [Cursor](https://cursor.com/marketplace/crowdstrike/crowdstrike-falcon-foundry) |
 | Antigravity CLI | `agy plugin install https://github.com/CrowdStrike/foundry-skills` | [Google](https://antigravity.google/docs/plugins) |
 
+> [!NOTE]
+> **Codex** has two install paths depending on how you signed in. The command above installs from the curated CLI marketplace, which **API-key and Amazon Bedrock** sessions load. If you authenticated Codex with a **ChatGPT** account, that marketplace isn't loaded — instead run `/plugins` inside Codex, search for `crowdstrike`, and install from the results.
+
 All five assistants have been verified end to end: the skills were loaded from a local clone, then used to build and deploy an app to a live Falcon Foundry tenant from the example prompt below.
 
 For local development with Claude Code, use `claude --plugin-dir /path/to/foundry-skills`. These skills follow the [Agent Plugins](https://agent-plugins.org) format and include a `.codex-plugin/plugin.json` manifest for native Codex discovery. See the [blog post](https://www.crowdstrike.com/tech-hub/ng-siem/build-falcon-foundry-apps-with-claude-code/) for a full walkthrough.