feat(workspace): adaptive content-aware column sizing and header double-click auto-fit (close #676)

[ZhuchkaTriplesix]

Summary

• Closes feat(workspace): adaptive content-aware column sizing and header double-click auto-fit in DataGrid #676.
• Resolves issue where short columns (e.g. app_id, country, numeric IDs) were forced to 120px and uniformly inflated when table width was less than viewport width.
• Lowered baseline minColumnWidth from 120 to 56px with dynamic header + content bounds.
• Added distributeResultGridSpareWidth to allocate spare viewport space to deficit/truncated columns rather than uniformly inflating compact columns.
• Implemented double-click auto-fit on column divider resize handles to compute full content/header width.
• Added material.Tooltip on header cells for long column names.
• Added unit tests for compact widths and spare width distribution, plus widget test for auto-fit double tap.