Add QOL features to tool call code

[ScriptSmith]

No description provided.

[greptile-apps]

Greptile Summary

This PR introduces a new shared HighlightedCode component using Shiki for syntax highlighting, consolidating duplicate code highlighting logic across CodeArtifact, HtmlArtifact, and ToolExecutionStep components.

Key Changes:

• Created reusable HighlightedCode component with Shiki integration for syntax highlighting
• Refactored CodeArtifact and HtmlArtifact to use the new component, removing ~50 lines of duplicate code
• Enhanced ToolExecutionStep with improved inline code preview UI featuring a header, better expand/collapse UX, and syntax highlighting
• Updated Storybook tests to handle syntax-highlighted text split across spans
• Added comprehensive Storybook stories for the new component

Issues Found:

• Missing error handling in clipboard copy function - unhandled promise rejections will occur if clipboard API fails

Confidence Score: 4/5

• This PR is safe to merge with one minor error handling issue that should be addressed
• The refactoring is well-executed with good code reuse, proper cleanup patterns, and comprehensive tests. The only issue is missing error handling in the clipboard copy function, which could cause unhandled promise rejections but won't break functionality.
• Pay attention to ui/src/components/HighlightedCode/HighlightedCode.tsx - add error handling to the copy function before merging

Important Files Changed

Filename	Overview
ui/src/components/HighlightedCode/HighlightedCode.tsx	New shared component for syntax-highlighted code using Shiki. Missing error handling in clipboard copy function.
ui/src/components/Artifact/CodeArtifact.tsx	Refactored to use HighlightedCode component, removing duplicate code. Clean simplification.
ui/src/components/ToolExecution/ToolExecutionStep.tsx	Enhanced inline code preview with improved UI, header, and syntax highlighting support via HighlightedCode.

_{Last reviewed commit: a57fbc5}