feat(ui): implement AbortChain and CleanEmptyRecords effects

Implement AbortChain and CleanEmptyRecords effects to allow
short-circuiting effect batches and purging cells with empty coordinates.
Update the App struct to support aborting effects during the application of
an effect batch.

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

src/ui/app.rs

@@ -229,6 +229,12 @@ pub struct App {
     /// Current grid layout, derived from model + view + drill_state.
     /// Rebuilt via `rebuild_layout()` after state changes.
     pub layout: GridLayout,
+    /// When set to true by an effect during `apply_effects`, the remaining
+    /// effects in the batch are skipped. The flag is reset at the start of
+    /// every `apply_effects` call. Use via the `AbortChain` effect — this is
+    /// the mechanism by which e.g. "advance at bottom-right" short-circuits
+    /// the trailing `EnterEditAtCursor` in a `CommitAndAdvance` chain.
+    pub abort_effects: bool,
     keymap_set: KeymapSet,
 }
 
@@ -272,6 +278,7 @@ impl App {
             buffers: HashMap::new(),
             transient_keymap: None,
             layout,
+            abort_effects: false,
             keymap_set: KeymapSet::default_keymaps(),
         }
     }
@@ -338,7 +345,8 @@ impl App {
             visible_rows: (self.term_height as usize).saturating_sub(8),
             visible_cols: {
                 let (fmt_comma, fmt_decimals) = parse_number_format(&view.number_format);
-                let col_widths = compute_col_widths(&self.workbook.model, layout, fmt_comma, fmt_decimals);
+                let col_widths =
+                    compute_col_widths(&self.workbook.model, layout, fmt_comma, fmt_decimals);
                 let row_header_width = compute_row_header_width(layout);
                 compute_visible_cols(
                     &col_widths,
@@ -353,8 +361,16 @@ impl App {
     }
 
     pub fn apply_effects(&mut self, effects: Vec<Box<dyn super::effect::Effect>>) {
+        self.abort_effects = false;
         for effect in effects {
             effect.apply(self);
+            if self.abort_effects {
+                // AbortChain (or another abort-setting effect) requested
+                // that the rest of this batch be skipped. Reset the flag so
+                // the next dispatch starts clean.
+                self.abort_effects = false;
+                break;
+            }
         }
         self.rebuild_layout();
     }
@@ -909,6 +925,73 @@ mod tests {
         app
     }
 
+    /// improvise-3zq (bug #2): `AddRecordRow` creates a cell with an empty
+    /// `CellKey` when no Page-axis categories supply coords — that cell
+    /// serialises as ` = 0` in .improv and re-appears on every records
+    /// toggle. Leaving records mode must clean up any such meaningless
+    /// records (inverse of the `SortData` that runs on entry).
+    #[test]
+    fn leaving_records_mode_cleans_empty_key_cells() {
+        use crate::model::cell::{CellKey, CellValue};
+        let mut app = records_model_with_two_rows();
+        // Simulate Tab-at-bottom-right having produced an empty-key cell.
+        app.workbook
+            .model
+            .set_cell(CellKey::new(vec![]), CellValue::Number(0.0));
+        assert!(
+            app.workbook
+                .model
+                .data
+                .iter_cells()
+                .any(|(k, _)| k.0.is_empty()),
+            "setup: empty-key cell should be present"
+        );
+        // Leave records mode via R.
+        app.handle_key(KeyEvent::new(KeyCode::Char('R'), KeyModifiers::NONE))
+            .unwrap();
+        assert!(
+            !app.layout.is_records_mode(),
+            "setup: should have left records mode"
+        );
+        assert!(
+            !app.workbook
+                .model
+                .data
+                .iter_cells()
+                .any(|(k, _)| k.0.is_empty()),
+            "empty-key records should be cleaned when leaving records mode"
+        );
+    }
+
+    /// improvise-3zq (bug #1): Enter on the bottom-right cell of records
+    /// view should commit and leave edit mode. Previously `CommitAndAdvance`
+    /// pushed an `EnterEditAtCursor` effect unconditionally, so the cursor
+    /// stayed put and we re-entered editing on the same cell.
+    #[test]
+    fn enter_at_bottom_right_of_records_view_exits_editing() {
+        let mut app = records_model_with_two_rows();
+        let last_row = app.layout.row_count() - 1;
+        let last_col = app.layout.col_count() - 1;
+        app.workbook.active_view_mut().selected = (last_row, last_col);
+
+        app.handle_key(KeyEvent::new(KeyCode::Char('i'), KeyModifiers::NONE))
+            .unwrap();
+        assert!(app.mode.is_editing(), "setup: should be editing");
+
+        app.handle_key(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE))
+            .unwrap();
+        assert!(
+            !app.mode.is_editing(),
+            "Enter at bottom-right should exit editing, got {:?}",
+            app.mode
+        );
+        assert!(
+            matches!(app.mode, AppMode::RecordsNormal),
+            "should return to RecordsNormal, got {:?}",
+            app.mode
+        );
+    }
+
     /// improvise-hmu: TAB on the bottom-right cell of records view should
     /// insert a new record below and move to the first cell of the new row
     /// in edit mode.
@@ -963,7 +1046,8 @@ mod tests {
             ("Month".to_string(), "Jan".to_string()),
             ("Region".to_string(), "East".to_string()),
         ]);
-        wb.model.set_cell(record_key.clone(), CellValue::Number(1.0));
+        wb.model
+            .set_cell(record_key.clone(), CellValue::Number(1.0));
         let mut app = App::new(wb, None);
 
         app.handle_key(KeyEvent::new(KeyCode::Char('>'), KeyModifiers::NONE))
@@ -1034,7 +1118,12 @@ mod tests {
             .unwrap();
 
         assert!(
-            !app.workbook.model.category("Region").unwrap().items.contains_key(""),
+            !app.workbook
+                .model
+                .category("Region")
+                .unwrap()
+                .items
+                .contains_key(""),
             "records-mode edits should not create empty category items"
         );
     }