feat(records): implement records mode for data entry

Implement a new "Records" mode for data entry.
- Add `RecordsNormal` and `RecordsEditing` to `AppMode` and `ModeKey` .
- `DataStore` now uses `IndexMap` and supports `sort_by_key()` to ensure
  deterministic row order.
- `ToggleRecordsMode` command now sorts data and switches to
  `RecordsNormal` .
- `EnterEditMode` command now respects records editing variants.
- `RecordsNormal` mode includes a new `o` keybinding to add a record row.
- `RecordsEditing` mode inherits from `Editing` and adds an `Esc` binding
  to return to `RecordsNormal` .
- Added `SortData` effect to trigger data sorting.
- Updated UI to display "RECORDS" and "RECORDS INSERT" mode names and
  styles.
- Updated keymaps, command registry, and view navigation to support these
  new modes.
- Added comprehensive tests for records mode behavior, including sorting
  and boundary conditions for Tab/Enter.

Co-Authored-By: fiddlerwoaroof/git-smart-commit (gemma-4-26B-A4B-it-UD-Q5_K_XL.gguf)

src/command/cmd/commit.rs

@@ -3,6 +3,7 @@ use crate::ui::app::AppMode;
 use crate::ui::effect::{self, Effect};
 
 use super::core::{Cmd, CmdContext};
+use super::grid::AddRecordRow;
 use super::navigation::{CursorState, EnterAdvance, viewport_effects};
 
 #[cfg(test)]
@@ -259,15 +260,31 @@ impl Cmd for CommitAndAdvance {
             }
             AdvanceDir::Right => {
                 let col_max = self.cursor.col_count.saturating_sub(1);
-                let nc = (self.cursor.col + 1).min(col_max);
-                effects.extend(viewport_effects(
-                    self.cursor.row,
-                    nc,
-                    self.cursor.row_offset,
-                    self.cursor.col_offset,
-                    self.cursor.visible_rows,
-                    self.cursor.visible_cols,
-                ));
+                let row_max = self.cursor.row_count.saturating_sub(1);
+                let at_bottom_right = self.cursor.row >= row_max && self.cursor.col >= col_max;
+
+                if at_bottom_right && ctx.is_records_mode() {
+                    let add = AddRecordRow;
+                    effects.extend(add.execute(ctx));
+                    effects.extend(viewport_effects(
+                        self.cursor.row + 1,
+                        0,
+                        self.cursor.row_offset,
+                        self.cursor.col_offset,
+                        self.cursor.visible_rows,
+                        self.cursor.visible_cols,
+                    ));
+                } else {
+                    let nc = (self.cursor.col + 1).min(col_max);
+                    effects.extend(viewport_effects(
+                        self.cursor.row,
+                        nc,
+                        self.cursor.row_offset,
+                        self.cursor.col_offset,
+                        self.cursor.visible_rows,
+                        self.cursor.visible_cols,
+                    ));
+                }
             }
         }
         effects.push(Box::new(effect::EnterEditAtCursor));