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/docs/calculator-ux.md

@@ -49,7 +49,10 @@ in as a per-ship result rather than a separate mode.
    units) that the loaded-column results use. At **full** the toggle
    shows the ship's cargo capacity; a **custom** load over that capacity
    is flagged as an error. With a zero cargo block there is no hold, so
-   the load is pinned to empty and the toggle is disabled.
+   the load is pinned to empty and the toggle is disabled. The bombing
+   and cargo-capacity rows have no goal-seek lock, but they still
+   reserve a hidden lock-slot placeholder so the value column stays
+   vertically aligned with the lockable rows above.
 3. **Planet area** — when an own planet is selected on the map, shows
    its MAT (overridable) and the single-turn build rate (ships per turn,
    turns per ship). The MAT follows the same lock idiom as the tech
@@ -125,17 +128,17 @@ fourth decimal as the user types: typing `1.2345` clamps the input to
 `util.Fixed*`; `Ceil3` is a display-only helper that lives in `pkg/calc`
 so the UI and Go share one implementation.
 
-## Create / load / delete
+## Create / load
 
 The name field is a combobox over the player's existing classes. Picking
 an existing class loads it as a template (so you can tweak and Create a
 new one); Create is disabled while the name is invalid or duplicate
-(reusing `lib/util/ship-class-validation.ts`). When a saved class is
-loaded, a Delete affordance appears. Create / Delete reuse the existing
-`createShipClass` / `removeShipClass` order-draft flow, so the optimistic
-overlay reflects the change immediately. Ship classes are immutable after
-creation (per `game/rules.txt`), so there is no edit — only Create-new
-and Delete.
+(reusing `lib/util/ship-class-validation.ts`). Create reuses the existing
+`createShipClass` order-draft flow, so the optimistic overlay reflects
+the change immediately. Ship classes are immutable after creation (per
+`game/rules.txt`), so there is no edit — only Create-new. Delete-class
+lives in the ship-classes table (`lib/active-view/table-ship-classes.svelte`),
+not the calculator.
 
 Selecting a class from the dropdown loads it **immediately**, the
 moment the option is clicked. (Native `change` only fires on blur in