Refactor Cart into checkerboard table

Closes: #173 (closed)

Removes clear all feature from: #233

This one improves focus behavior in the cart, moving cart items and deleting items from the cart.

clive/__private/ui/operations/cart.py

 from __future__ import annotations
 
-import time
 from typing import TYPE_CHECKING, Sequence
 
 from textual import on
@@ -240,8 +239,9 @@ class Cart(BaseScreen):
     def _handle_remove_event(self, triggering_widget: CartItem) -> None:
         def devalue_indexes(rows: Sequence[CartItem]) -> None:
             for row in rows:
-                row.reactive_idx = row.idx - 1
-        start_index = triggering_widget.idx
+                row.reactive_idx = row.reactive_idx - 1
+
+        start_index = triggering_widget.reactive_idx
         rows = self.query(CartItem)[start_index:]
         devalue_indexes(rows)
         self._cart_table.set_evenness_styles(rows, starting_index=start_index)
@@ -264,24 +264,19 @@ class Cart(BaseScreen):
 
     @on(CartItem.Delete)
     async def remove_item(self, event: CartItem.Delete) -> None:
-        # logger.debug(f"REMOVE CLICKED, DEVALUATION IN PROGRESS?: {self._index_devaluation_in_progress}")
-        # if self._index_devaluation_in_progress:
-        #     self.task.cancel()
-        #     while self._index_devaluation_in_progress:
-        #         logger.debug("DEVALUATION IN PROGRESS")
-        #     logger.debug("DEVALUATION DONE")
-        #     self.task.uncancel()
         self._removal_in_progress = True
+        logger.debug(f"(DELETE STARTED), LEN OF ROWS: {len(self.query(CliveCheckerboardTableRow))}, IDX TO REMOVE: {event.widget.reactive_idx}")
         await self.query(CliveCheckerboardTableRow)[event.widget.reactive_idx].remove()
         self.profile_data.cart.remove(event.widget.operation)
         self._handle_remove_event(triggering_widget=event.widget)
         self.app.trigger_profile_data_watchers()
+        logger.debug("DELETE FINISHED")
         self._removal_in_progress = False
 
-        if len(self.app.world.profile_data.cart) > 0 and event.widget.idx == 0:
+        if len(self.app.world.profile_data.cart) > 0 and event.widget.reactive_idx == 0:
             # disable first ButtomMoveUp if first element was removed
             self.query(ButtonMoveUp)[0].disabled = True
-        if 0 < len(self.app.world.profile_data.cart) == event.widget.idx:
+        if 0 < len(self.app.world.profile_data.cart) == event.widget.reactive_idx:
             # disable last ButtonMoveDown if only last element was removed
             self.query(ButtonMoveDown)[-1].disabled = True
 
@@ -295,13 +290,13 @@ class Cart(BaseScreen):
         self._update_values_of_swapped_rows(from_index=event.from_idx, to_index=event.to_idx)
         # focus item that was moved
         for cart_item in self.query(CartItem):
-            if event.to_idx == cart_item.idx:
+            if event.to_idx == cart_item.reactive_idx:
                 self.app.set_focus(cart_item)
 
     @on(CartItem.Focus)
     def focus_item(self, event: CartItem.Focus) -> None:
         for cart_item in self.query(CartItem):
-            if event.target_idx == cart_item.idx:
+            if event.target_idx == cart_item.reactive_idx:
                 self.app.set_focus(cart_item)
                 if event.focus_button:
                     cart_item.query_one(f"#{event.focus_button}").focus()