Virtualized results grid component

[GordonBeeming]

Description

High-performance results grid for displaying query output using virtual scrolling.

Implementation

• @tanstack/react-table for column definitions, sorting, resizing
• @tanstack/react-virtual for virtual scrolling (only render visible rows)
• Ring buffer approach: keep max ~500K rows in memory, evict oldest

Acceptance Criteria

• Tabular grid displaying query results
• Virtual scrolling: handles 100K+ rows smoothly (60fps)
• Column headers show name and data type
• Proper type formatting: dates, numbers, NULL (displayed distinctly)
• Row numbers column
• Alternating row colors for readability
• Selection: click cell, shift+click range, Ctrl+A all