Bomb target location (same logic as naval invasions) (#2309)

## Description:

Added logic to hydro/atom bombs - using same FX as the boat invasion
(keeping PR smaller, can add more UX for hydro/atoms later)

Only you & teammates can see the target.

<img width="747" height="356" alt="image"
src="https://github.com/user-attachments/assets/bc1aaec0-8b41-4def-92ee-9f076a8cd550"
/>


Viewpoint from two players:
<img width="1667" height="680" alt="image"
src="https://github.com/user-attachments/assets/76e96ad1-af09-4584-a71a-823c85b6e26b"
/>



## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

w.o.n

src/client/graphics/layers/FxLayer.ts

@@ -30,6 +30,7 @@ export class FxLayer implements Layer {
 
   private allFx: Fx[] = [];
   private boatTargetFxByUnitId: Map<number, TargetFx> = new Map();
+  private nukeTargetFxByUnitId: Map<number, TargetFx> = new Map();
 
   constructor(private game: GameView) {
     this.theme = this.game.config().theme();
@@ -87,6 +88,28 @@ export class FxLayer implements Layer {
     }
   }
 
+  // Register a persistent nuke target marker for the current player or teammates
+  private createNukeTargetFxIfOwned(unit: UnitView) {
+    const my = this.game.myPlayer();
+    if (!my) return;
+    // Show nuke marker owned by the player or by players on the same team
+    if (
+      (unit.owner() === my || my.isOnSameTeam(unit.owner())) &&
+      unit.isActive()
+    ) {
+      if (!this.nukeTargetFxByUnitId.has(unit.id())) {
+        const t = unit.targetTile();
+        if (t !== undefined) {
+          const x = this.game.x(t);
+          const y = this.game.y(t);
+          const fx = new TargetFx(x, y, 0, true);
+          this.allFx.push(fx);
+          this.nukeTargetFxByUnitId.set(unit.id(), fx);
+        }
+      }
+    }
+  }
+
   onBonusEvent(bonus: BonusEventUpdate) {
     if (this.game.player(bonus.player) !== this.game.myPlayer()) {
       // Only display text fx for the current player
@@ -135,13 +158,19 @@ export class FxLayer implements Layer {
         }
         break;
       }
-      case UnitType.AtomBomb:
+      case UnitType.AtomBomb: {
+        this.createNukeTargetFxIfOwned(unit);
+        this.onNukeEvent(unit, 160);
+        break;
+      }
       case UnitType.MIRVWarhead:
         this.onNukeEvent(unit, 70);
         break;
-      case UnitType.HydrogenBomb:
+      case UnitType.HydrogenBomb: {
+        this.createNukeTargetFxIfOwned(unit);
         this.onNukeEvent(unit, 160);
         break;
+      }
       case UnitType.Warship:
         this.onWarshipEvent(unit);
         break;
@@ -270,6 +299,11 @@ export class FxLayer implements Layer {
 
   onNukeEvent(unit: UnitView, radius: number) {
     if (!unit.isActive()) {
+      const fx = this.nukeTargetFxByUnitId.get(unit.id());
+      if (fx) {
+        fx.end();
+        this.nukeTargetFxByUnitId.delete(unit.id());
+      }
       if (!unit.reachedTarget()) {
         this.handleSAMInterception(unit);
       } else {