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/en.ts

@@ -364,7 +364,6 @@ const en = {
 	"game.calculator.name.placeholder": "new class name",
 	"game.calculator.name.existing": "your ship classes",
 	"game.calculator.action.create": "create",
-	"game.calculator.action.delete": "delete",
 	"game.calculator.col.ship": "ship",
 	"game.calculator.col.tech": "tech",
 	"game.calculator.field.drive": "drive",

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",

ui/frontend/src/lib/sidebar/calculator-tab.svelte

@@ -204,11 +204,6 @@ long-lived planning tool. `ensureGame` resets it when the game changes.
 		nameValidation.ok ? "" : i18n.t(nameInvalidKeyMap[nameValidation.reason]),
 	);
 	const canCreate = $derived(nameValidation.ok && draft !== undefined);
-	const canDelete = $derived(
-		cs.loadedExisting !== null &&
-			existingNames.includes(cs.loadedExisting) &&
-			draft !== undefined,
-	);
 
 	// Per-block modernization upgrade cost (current tech → target tech).
 	const modernCosts = $derived.by(() => {
@@ -489,16 +484,6 @@ long-lived planning tool. `ensureGame` resets it when the game changes.
 		cs.loadedExisting = created.name;
 	}
 
-	async function deleteClass(): Promise<void> {
-		if (cs.loadedExisting === null || draft === undefined) return;
-		await draft.add({
-			kind: "removeShipClass",
-			id: crypto.randomUUID(),
-			name: cs.loadedExisting,
-		});
-		cs.loadedExisting = null;
-	}
-
 	const LOCK_LABELS: Record<LockableOutputId, string> = $derived({
 		emptyMass: i18n.t("game.calculator.out.mass"),
 		loadedMass: i18n.t("game.calculator.out.mass"),
@@ -608,16 +593,6 @@ long-lived planning tool. `ensureGame` resets it when the game changes.
 			</button>
 		{/if}
 	</div>
-	{#if cs.mode === "ship" && canDelete}
-		<button
-			type="button"
-			class="delete"
-			data-testid="calculator-delete"
-			onclick={() => void deleteClass()}
-		>
-			{i18n.t("game.calculator.action.delete")} {cs.loadedExisting}
-		</button>
-	{/if}
 
 	<ShipDesignArea
 		bind:blocks={cs.blocks}
@@ -704,6 +679,7 @@ long-lived planning tool. `ensureGame` resets it when the game changes.
 					<span class="val" data-testid="calculator-out-bombing">
 						{fmt(result.outputs?.bombing)}
 					</span>
+					<span class="lock-slot" aria-hidden="true">🔓</span>
 				</span>
 				<span></span>
 			</div>
@@ -713,6 +689,7 @@ long-lived planning tool. `ensureGame` resets it when the game changes.
 					<span class="val" data-testid="calculator-out-cargo-capacity">
 						{fmt(result.outputs === null ? null : result.cargoCapacity)}
 					</span>
+					<span class="lock-slot" aria-hidden="true">🔓</span>
 				</span>
 				<span></span>
 			</div>
@@ -893,8 +870,7 @@ long-lived planning tool. `ensureGame` resets it when the game changes.
 	.name[aria-invalid="true"] {
 		border-color: var(--color-danger);
 	}
-	.create,
-	.delete {
+	.create {
 		font: inherit;
 		font-size: 0.8rem;
 		padding: 0.25rem 0.55rem;
@@ -912,10 +888,6 @@ long-lived planning tool. `ensureGame` resets it when the game changes.
 		opacity: 0.5;
 		cursor: not-allowed;
 	}
-	.delete {
-		color: var(--color-danger);
-		align-self: flex-start;
-	}
 	.load {
 		display: flex;
 		align-items: center;
@@ -1036,6 +1008,12 @@ long-lived planning tool. `ensureGame` resets it when the game changes.
 		cursor: not-allowed;
 		opacity: 0.2;
 	}
+	.lock-slot {
+		flex: none;
+		font-size: 0.7rem;
+		line-height: 1;
+		visibility: hidden;
+	}
 	.planet {
 		border-top: 1px solid var(--color-border-subtle);
 		padding-top: 0.5rem;