Add a prominent grab tab that extends from the resize divider:
- 8px thin divider with centered grip dots
- 28px wide grab tab with rounded corners (right side only)
- Visible knurled texture (vertical ridges) for tactile appearance
- Handle is 36px total width with negative margin to overlap preview
- Hover states change colors to blue for visual feedback
This makes it much easier to grab and resize the sidebar panel,
especially when collapsed on mobile devices.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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