###
Edit modeEdit cell values directly in the grid and write the result back to the source file,
preserving its original encoding and delimiter.
* Toggle edit mode with **Ctrl+E** (or **Ctrl+R**), via the right-click menu, or the
status bar.
* Start editing a cell with **F2** or by **double-clicking** it.
* **Enter accepts the change, **Esc** cancels it.
* Delete whole rows with **Ctrl+X** or the right-click menu (*Delete row(s)*). The
selected rows are removed; with no selection the row under the cursor is deleted.
* **Ctrl+S** saves the file. Saving is **atomic** (write-to-temp + replace) so a failed
write never corrupts the original file. Encoding, delimiter and comment handling are
preserved on save.
* The status bar shows the current state: `EDIT`, `EDIT *` (unsaved edit) or `MODIFIED *`.
* If you close the viewer or reload the document with unsaved changes, you are asked
whether to save first.
###
Transform mode (column workbench)A side panel for reshaping the table without touching the source file, with a **live
preview** directly in the grid.
Toggle transform mode with **Ctrl+T**, via the right-click menu, or the status bar.
The sidebar groups the actions by purpose (each group is colour-coded):
| Group | Actions | Description |
|-------|---------|-------------|
| **Ordering | Up / Down | Move the selected column |
| **Columns | Add / Remove / Rename | Add new (virtual) columns, drop or rename existing ones. *Add* accepts several names separated by `;` |
| **Cell values** | Set all cells / Fill empty cells / Enumerate cells | Set a constant value, fill only the empty cells, or number rows over a `start:stop` range |
| **Load / Save** | Load / Save transformation | Persist the whole transformation as a JSON file and reload it later |
| **Export | Export CSV / Delimiter / Number format | Write the transformed table to a new CSV; choose the export delimiter (`;` `,` TAB) and number format (keep `original`, force `.` or force `,`) |
| **Apply | Apply to grid | Render the transformation live in the grid; the button turns into *Reset grid view* |
* The input field uses a placeholder hint (*"Value / name / enumeration start:stop"*).
* **Apply to grid** shows the transformed columns, headers and values in the grid itself
(read-only preview). The status bar shows a `TRANSFORM` indicator. Press the button
again (now *Reset grid view*) to return to the normal view. The source data is never
modified by the preview.
