[copyberry]

Store generated image items as attachment references

What changed

• Upload generated images to the attachment store and expose fileId in image-generation items when available, with inline result fallback on upload or decoding failure.
• Preserve file references through legacy events, persisted rollouts, thread history, and task output summaries. Keep model-facing image preparation separate.
• Add attachment request tags and mark generated-image uploads with usage=image_gen, preserving the thread's ephemeral setting.
• Update public schemas and SDK types to accept either image representation, retain the Python ImageGenerationThreadItem alias, and prefer fileId when reading records containing both fields.

Testing

Add coverage for file-backed generation and rollout persistence, legacy history replay, inline and transitional serialization, task output visibility, and Python SDK alias compatibility.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	🔄 Running since 2026-10-15T19:51:35.235244Z	eab910c	PR opened

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