add image preview

[Alex2251]

Add image preview

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Summary by cubic

Added image preview in the chat composer so image attachments show a thumbnail before sending. Non-image files still show the file icon.

• New Features
  • Display inline thumbnail with tooltip for image attachments using object URLs, with cleanup on unmount and URL change to prevent leaks.
  • Store and pass the original File in attachment state and components to generate previews.

^{Written for commit e72e504. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 4 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="frontend/src/components/chat/MessageComposer/Attachment.tsx">

<violation number="1" location="frontend/src/components/chat/MessageComposer/Attachment.tsx:28">
P2: Object URLs created for image previews are never revoked, which can leak memory when files change or the component unmounts.</violation>
</file>

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