[FR-315] feat: integrate image generation model

[agatha197]

resolves https://lablup.atlassian.net/browse/FR-315

Added image generation capability to the LLM chat interface. Users can now:

• Toggle between normal chat and image generation modes
• Generate images using prompts via the Flux inference endpoint
• View generated images inline within the chat
• Switch modes using a new picture button in the chat input
• See loading states during image generation

Added "Picture" translation strings across all supported languages.

Checklist:

• Mention to the original issue
• Documentation
• Minium required manager version
• Specific setting for review (eg., KB link, endpoint or how to setup)
• Minimum requirements to check during review
• Test case(s) to demonstrate the difference of before/after

[agatha197]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• [FR-315] feat: integrate image generation model #2997 👈 (View in Graphite)
• [FR-46] fix: The ScrollBottomHandlerButton is displayed even when the chat message is empty. #2996
• [FR-22] feature: provide token-related information #2995 : 1 other dependent PR (#2998 )
• [FR-22] feature: handle image and text attachments in chat modal #2993
• refactor: replace ChatInput with antdx component #2972
• main

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