Add cell-selection-custom-palette samples for Grid, Hierarchical Grid, and Tree Grid

[Copilot]

• Review changes made to grid sample by @tishko0
• Apply comprehensive palette structure to hierarchical grid sample
• Apply comprehensive palette structure to tree grid sample
• Add multiple selection modes (cell, row, column) to both samples
• Add filtering support to both samples
• Add sortable columns to both samples
• Remove width constraints from all columns for auto-sizing

Summary

Updated all three cell-selection-custom-palette samples to remove column width constraints, allowing the grids to take all available space and auto-size columns.

Changes Applied

All Three Samples (Grid, Hierarchical Grid, Tree Grid):

• ✅ Removed all width properties from columns
• ✅ Removed minWidth and maxWidth properties from hierarchical grid columns
• ✅ Grids now auto-size to fill available space
• ✅ Columns distribute width automatically

CSS Palette Structure

All samples include a comprehensive palette with:

• Base palette colors (primary, secondary, accent, success variants)
• Core cell selection properties
• Enhanced selection states (range, hover, focus)
• Header selection styling
• Row selection integration
• Selection indicators and borders

Screenshots

Grid with Auto-Sized Columns:

Shows the grid taking full available width with:

• Custom blue (#0062a3) selection background
• Row selection checkboxes
• Column filtering enabled
• Sortable columns
• Auto-sized columns without width constraints

Original prompt

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This section details on the original issue you should resolve

<issue_title>Create palletes sample for the cell selection topic.</issue_title>
<issue_description>Create samples with custom palletes for the cell-selectiontopic. Refer to cell selection samples in this repo and create samples. The samples should look like the ones in this PRs:
Grid: #929
Hgrid and Tgrid: #927</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #931

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[tishko0]

@copilot The samples are lacking palette structure and selection options. I have updated the grid sample. Can you please review the changes on it and apply them to hgrid and tgrid samples

[Copilot]

@copilot The samples are lacking palette structure and selection options. I have updated the grid sample. Can you please review the changes on it and apply them to hgrid and tgrid samples

Applied the palette structure and selection options from the grid sample to both hierarchical grid and tree grid samples in commit 36bd6f6.

Changes include:

• Comprehensive CSS palette with semantic color variables in :root
• .custom-selection-palette class with all selection styling properties
• Multiple selection modes enabled (cell, row, column)
• Filtering and sortable columns added
• Column widths for better layout

[tishko0]

@copilot Please remove the min/max width of the columns as we want the grid to be taking all the available space on its own.

[tishko0]

@copilot Please remove the min/max width of the columns as we want the grid to be taking all the available space on its own.

@copilot please update

[Copilot]

@copilot Please remove the min/max width of the columns as we want the grid to be taking all the available space on its own.

Removed all width, minWidth, and maxWidth properties from columns in all three samples (Grid, Hierarchical Grid, and Tree Grid) in commit 2c98a8e. The grids now auto-size to fill available space.

@copilot Please remove the min/max width of the columns as we want the grid to be taking all the available space on its own.

@copilot please update

Updated in commit 2c98a8e - removed all column width constraints from all three samples.