feat(kanban): hide "Seleccionar Aleatorio" in done columns

The random-pick menu entry is meaningless for done columns — cards there
are already finished and now get auto-archived after 30 days (issue
0092). Gate the Menu.Item on !column.is_done so the action only appears
in active columns.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/KanbanColumn.tsx

@@ -547,14 +547,16 @@ function KanbanColumnImpl({
                       </Stack>
                     </Popover.Dropdown>
                   </Popover>
-                  <Menu.Item
-                    leftSection={<IconDice5 size={14} />}
-                    data-test="column-random-pick"
-                    disabled={cards.filter((c) => !c.locked).length === 0}
-                    onClick={() => onPickRandom(column.id)}
-                  >
-                    Seleccionar Aleatorio
-                  </Menu.Item>
+                  {!column.is_done && (
+                    <Menu.Item
+                      leftSection={<IconDice5 size={14} />}
+                      data-test="column-random-pick"
+                      disabled={cards.filter((c) => !c.locked).length === 0}
+                      onClick={() => onPickRandom(column.id)}
+                    >
+                      Seleccionar Aleatorio
+                    </Menu.Item>
+                  )}
                   <Menu.Item
                     leftSection={<ArchiveIcon size={14} />}
                     onClick={() => onMoveColumnLocation(column.id, isInSidebar ? "board" : "sidebar")}