Datatype-aware editor: expanded long-text cell editor

[dasunNimantha]

Summary

Long text values (text, varchar(max), nvarchar(max), clob, blobs rendered as text, multi-line strings) are difficult to edit in a single-line ag-grid cell. The cell either truncates the content or scrolls horizontally inside a tiny input. Users want an expanded editor with proper wrapping and multi-line input.

Current behavior

Column definitions at src/components/DataGrid/DataGrid.tsx:548-612 do not set a cellEditor for text columns — ag-grid uses its default single-line text editor.

There is no mechanism to detect "long text" and switch to a larger editor.

Proposed approach

1. Build a LongTextCellEditor ag-grid editor:
   • Renders a small popup textarea (or a side / bottom-docked panel) sized for multi-line input.
   • Word-wrap on by default; preserves newlines and tabs.
   • Has Save and Cancel buttons; Esc cancels; Ctrl+Enter (or Cmd+Enter) saves.
   • Shows character / line count for very large values.
2. Wire into column defs at src/components/DataGrid/DataGrid.tsx:548-612 for text-class types and any value whose length exceeds a threshold (e.g. > 200 chars or contains newlines), so short string columns continue to use the default inline editor.
3. Support null entry.

Acceptance criteria

• Text columns over a configurable length threshold open the expanded editor
• Multi-line content (with newlines and tabs) is preserved on save
• Esc cancels and Ctrl+Enter saves
• No regression on short text columns (still inline editor)
• Null entry supported
• Component test covers open / type / save / cancel paths

Out of scope

• Rich-text or markdown rendering inside cells.
• Diff view for before / after edit.