🐛 fix HUD overlay zoom + add red center crosshair

Text overlay now uses a dedicated HUD camera (zoom=1, fixed scroll)
so it's never scaled by the world zoom. World objects and HUD objects
are separated via camera ignore lists. Added red screen-center
crosshair to HUD layer as a precise alignment reference.

src/test/ZoomTestScene.ts

@@ -19,6 +19,9 @@ const SNAPSHOT_EVERY   = 2000   // ms between periodic log snapshots
  */
 export class ZoomTestScene extends Phaser.Scene {
   private logText!: Phaser.GameObjects.Text
+  private hudCamera!: Phaser.Cameras.Scene2D.Camera
+  private worldObjects: Phaser.GameObjects.GameObject[] = []
+  private hudObjects: Phaser.GameObjects.GameObject[] = []
   private keys!: {
     up:    Phaser.Input.Keyboard.Key
     down:  Phaser.Input.Keyboard.Key
@@ -43,19 +46,18 @@ export class ZoomTestScene extends Phaser.Scene {
     this.drawGrid()
     this.setupCamera()
     this.setupInput()
-    this.createOverlay()
+    this.createHUD()
+    this.setupCameras()
   }
 
   /**
    * Draws the static world grid into world space.
-   * - Faint tile lines on every tile boundary
-   * - Small green crosshairs every MARKER_EVERY tiles
-   * - Yellow labeled crosshairs every LABEL_EVERY tiles
-   * - Red world border
+   * All objects are registered in worldObjects for HUD-camera exclusion.
    */
   private drawGrid(): void {
     const worldPx = GRID_TILES * TILE_SIZE
     const g = this.add.graphics()
+    this.worldObjects.push(g)
 
     // Background fill
     g.fillStyle(0x111811)
@@ -90,12 +92,13 @@ export class ZoomTestScene extends Phaser.Scene {
     // Coordinate labels at LABEL_EVERY intersections
     for (let tx = 0; tx <= GRID_TILES; tx += LABEL_EVERY) {
       for (let ty = 0; ty <= GRID_TILES; ty += LABEL_EVERY) {
-        this.add.text(
+        const label = this.add.text(
           tx * TILE_SIZE + 4,
           ty * TILE_SIZE + 4,
           `${tx},${ty}`,
           { fontSize: '9px', color: '#ffff88', fontFamily: 'monospace' }
         ).setDepth(1)
+        this.worldObjects.push(label)
       }
     }
 
@@ -148,7 +151,6 @@ export class ZoomTestScene extends Phaser.Scene {
       const newZoom = Phaser.Math.Clamp(cam.zoom - Math.sign(dy) * ZOOM_STEP, MIN_ZOOM, MAX_ZOOM)
       cam.setZoom(newZoom)
 
-      // Log after Phaser has applied the zoom (next microtask so values are updated)
       setTimeout(() => {
         this.writeLog('zoom', {
           direction:      dy > 0 ? 'out' : 'in',
@@ -176,9 +178,25 @@ export class ZoomTestScene extends Phaser.Scene {
   }
 
   /**
-   * Creates the fixed HUD text overlay (scroll factor 0 = screen space).
+   * Creates all HUD elements: log overlay and screen-center crosshair.
+   * All objects are registered in hudObjects for main-camera exclusion.
+   * Uses a dedicated HUD camera (zoom=1, fixed) so elements are never scaled.
    */
-  private createOverlay(): void {
+  private createHUD(): void {
+    const w = this.scale.width
+    const h = this.scale.height
+
+    // Screen-center crosshair (red)
+    const cross = this.add.graphics()
+    const arm = 16
+    cross.lineStyle(1, 0xff2222, 0.9)
+    cross.lineBetween(w / 2 - arm, h / 2, w / 2 + arm, h / 2)
+    cross.lineBetween(w / 2, h / 2 - arm, w / 2, h / 2 + arm)
+    cross.fillStyle(0xff2222, 1.0)
+    cross.fillCircle(w / 2, h / 2, 2)
+    this.hudObjects.push(cross)
+
+    // Log text overlay
     this.logText = this.add.text(10, 10, '', {
       fontSize: '13px',
       color: '#e8e8e8',
@@ -186,16 +204,27 @@ export class ZoomTestScene extends Phaser.Scene {
       padding: { x: 10, y: 8 },
       lineSpacing: 3,
       fontFamily: 'monospace',
-    })
-      .setScrollFactor(0)
-      .setDepth(100)
+    }).setDepth(100)
+    this.hudObjects.push(this.logText)
+  }
+
+  /**
+   * Adds a dedicated HUD camera (zoom=1, no scroll) and separates
+   * world objects from HUD objects so neither camera renders both layers.
+   */
+  private setupCameras(): void {
+    this.hudCamera = this.cameras.add(0, 0, this.scale.width, this.scale.height)
+    this.hudCamera.setScroll(0, 0)
+    this.hudCamera.setZoom(1)
+
+    this.cameras.main.ignore(this.hudObjects)
+    this.hudCamera.ignore(this.worldObjects)
   }
 
   update(_time: number, delta: number): void {
     this.handleKeyboard(delta)
     this.updateOverlay()
 
-    // Periodic snapshot
     this.snapshotTimer += delta
     if (this.snapshotTimer >= SNAPSHOT_EVERY) {
       this.snapshotTimer = 0
@@ -231,26 +260,16 @@ export class ZoomTestScene extends Phaser.Scene {
     const cam = this.cameras.main
     const ptr = this.input.activePointer
 
-    // Viewport size in world pixels (what is actually visible)
     const vpWidthPx     = cam.width  / cam.zoom
     const vpHeightPx    = cam.height / cam.zoom
-
-    // Viewport size in tiles
     const vpWidthTiles  = vpWidthPx  / TILE_SIZE
     const vpHeightTiles = vpHeightPx / TILE_SIZE
-
-    // Camera center in world coords
     const centerWorldX  = cam.scrollX + vpWidthPx  / 2
     const centerWorldY  = cam.scrollY + vpHeightPx / 2
-
-    // Tile under mouse
     const mouseTileX    = Math.floor(ptr.worldX / TILE_SIZE)
     const mouseTileY    = Math.floor(ptr.worldY / TILE_SIZE)
-
-    // Tile at camera center
     const centerTileX   = Math.floor(centerWorldX / TILE_SIZE)
     const centerTileY   = Math.floor(centerWorldY / TILE_SIZE)
-
     const renderer      = this.game.renderer.type === Phaser.WEBGL ? 'WebGL' : 'Canvas'
 
     const lines = [