[codex] Update README for v0.1.0 release guidance

[aviaviavi]

Summary

• Point the CMake FetchContent snippet at the released v0.1.0 tag instead of main.
• Update the usage example to use metadata-style JSON property names rather than event/package.
• Document that Scarf analytics are processed asynchronously and may take a couple hours to appear.
• Add a note that CI currently validates Linux and macOS, while Windows/MSVC is intended but not covered yet.

Validation

• git diff --check

This is a documentation-only change.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 953bf8ae40

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Preserve the recognized version field in events

When users copy this Scarf Gateway/Event Collection example, sending release instead of the recognized version/$version field means the event can still be accepted but Scarf will not populate its package-version analytics/export dimension unless the endpoint has a custom mapping. The guidance was meant to avoid overloading event/package, but dropping the version field regresses the release-segmentation data the previous example produced; keep a documented version field alongside the metadata-style names.

Useful? React with 👍 / 👎.