fix(ui): F8-06 calculator polish — drop delete-class button, reserve lock slot

- Remove the `delete <ship_class_name>` button (and `deleteClass`,
  `canDelete`, `.delete` CSS, `game.calculator.action.delete` i18n key)
  from the calculator. Delete-class lives in the ship-classes table —
  the broader rework will land under #53.
- Bombing and cargo-capacity rows now reserve a hidden lock-slot
  placeholder so their value column lines up vertically with the
  mass/speed/attack/defence rows (which carry a lock button).

ui/frontend/src/lib/i18n/locales/ru.ts

@@ -365,7 +365,6 @@ const ru: Record<keyof typeof en, string> = {
 	"game.calculator.name.placeholder": "имя нового класса",
 	"game.calculator.name.existing": "ваши классы кораблей",
 	"game.calculator.action.create": "создать",
-	"game.calculator.action.delete": "удалить",
 	"game.calculator.col.ship": "корабль",
 	"game.calculator.col.tech": "технологии",
 	"game.calculator.field.drive": "двигатель",