Add Jump to File button and Git diff viewer

[xingyaoww]

This PR addresses issue #5716 by adding a Jump to File button in the ExpandableMessage component and implementing a Git diff viewer in the file explorer.

Changes made:

• Added a Jump to File button in the ExpandableMessage component
• Created a GitDiffViewer component
• Implemented a getGitDiff function in the OpenHands API
• Created a useGitDiff hook to fetch git diffs
• Updated the FileExplorer component to display git diffs

Fixes #5716

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To run this PR locally, use the following command:

docker run -it --rm   -p 3000:3000   -v /var/run/docker.sock:/var/run/docker.sock   --add-host host.docker.internal:host-gateway   -e SANDBOX_RUNTIME_CONTAINER_IMAGE=docker.all-hands.dev/all-hands-ai/runtime:0ee4339-nikolaik   --name openhands-app-0ee4339   docker.all-hands.dev/all-hands-ai/openhands:0ee4339