refactor!: unify records and pivot mode cell handling

Refactor records mode to use synthetic CellKeys (_Index, _Dim) for all columns,
allowing uniform handling of display values and edits across both pivot and
records modes.

- Introduce `synthetic_record_info` to extract metadata from synthetic keys.
- Update `GridLayout::cell_key` to return synthetic keys in records mode.
- Add `GridLayout::resolve_display` to handle value resolution for synthetic
  keys.
- Replace `records_col` and `records_value` in `CmdContext` with a unified
  `display_value`.
- Update `EditOrDrill` and `AddRecordRow` to use synthetic key detection.
- Refactor `CommitCellEdit` to use a shared `commit_cell_value` helper.

BREAKING CHANGE: CmdContext fields `records_col` and `records_value` are replaced by
`display_value` .
Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/gemma-4-31B-it-GGUF:UD-Q5_K_XL)

src/ui/app.rs

@@ -164,28 +164,34 @@ impl App {
             none_cats: layout.none_cats.clone(),
             view_back_stack: self.view_back_stack.clone(),
             view_forward_stack: self.view_forward_stack.clone(),
-            records_col: if layout.is_records_mode() {
-                Some(layout.col_label(sel_col))
-            } else {
-                None
+            display_value: {
+                let key = layout.cell_key(sel_row, sel_col);
+                if let Some(k) = &key {
+                    if let Some((idx, dim)) = crate::view::synthetic_record_info(k) {
+                        // Synthetic records key: check pending drill edits first
+                        self.drill_state.as_ref()
+                            .and_then(|s| s.pending_edits.get(&(idx, dim)).cloned())
+                            .or_else(|| layout.resolve_display(k))
+                            .unwrap_or_default()
+                    } else {
+                        self.model.get_cell(k)
+                            .map(|v| v.to_string())
+                            .unwrap_or_default()
+                    }
+                } else {
+                    String::new()
+                }
             },
-            records_value: if layout.is_records_mode() {
-                // Check pending edits first, then fall back to original
-                let col_name = layout.col_label(sel_col);
-                let pending = self.drill_state.as_ref().and_then(|s| {
-                    s.pending_edits.get(&(sel_row, col_name.clone())).cloned()
-                });
-                pending.or_else(|| layout.records_display(sel_row, sel_col))
-            } else {
-                None
-            },
-            // Approximate visible rows/cols from terminal size.
+            // Approximate visible rows from terminal size.
             // Chrome: title(1) + border(2) + col_headers(n_col_levels) + separator(1)
             //         + tile_bar(1) + status_bar(1) = ~8 rows of chrome.
             visible_rows: (self.term_height as usize).saturating_sub(8),
-            // Visible cols depends on column widths — use a rough estimate.
-            // The grid renderer does the precise calculation.
-            visible_cols: ((self.term_width as usize).saturating_sub(30) / 12).max(1),
+            visible_cols: {
+                let (fmt_comma, fmt_decimals) = parse_number_format(&view.number_format);
+                let col_widths = compute_col_widths(&self.model, &layout, fmt_comma, fmt_decimals);
+                let row_header_width = compute_row_header_width(&layout);
+                compute_visible_cols(&col_widths, row_header_width, self.term_width, view.col_offset)
+            },
             expanded_cats: &self.expanded_cats,
             key_code: key,
         }