Use theme palette for ToolGrid colors

[Irozuku]

Summary

This pull request updates the ToolGrid component to use the application's theme palette instead of hardcoded color values. Specifically, divider and text colors now reference the theme configuration.

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Type of Change

Check all that apply like this [x]:

• Backend change
• Frontend change
• CI / Workflow change
• Build / Packaging change
• Bug fix
• Documentation

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Changes (by file)

Briefly list the important modified files and what was done.

• ToolGrid.jsx: Replaced hardcoded divider and text colors with values from the theme palette.

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Testing (optional)

• Verify that divider and text colors in ToolGrid match the current theme.
• Confirm appearance remains correct in both light and dark modes.