Support follow-up edits for generated images (#5712)

* Support follow-up edits for generated images

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Fix generated image edit references

* Fix image generation tool guard

* Replay OpenAI image reasoning refs

* Capture streamed OpenAI reasoning refs

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Trigger Gather Town test

* Use OpenAI response context for image edits

* Studio: improve generated image card UI

* Studio: refine generated image overlay and edit context

* Studio: animate generated image loading state

* Studio: bind generated-image edits to selected image

* Studio: drop empty external assistant payloads

* Studio: guard generated image clipboard MIME

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Simplify image generation edit wiring

* Remove temporary image generation test changes

* Preserve explicit image edit references

* Scope image edit references to threads

* Harden OpenAI image edit replay handling

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update image generation tool event test

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>