fix: domino endpoint tap on empty board + status update on select

- Empty board now returns hit on any board tap when active endpoint set
- Status text updates immediately when tile is selected/deselected
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/js/modules/domino/canvas/board.js

@@ -121,6 +121,11 @@ export class DominoBoard {
     const rightEp = this.layout.endpoints.right;
     const radius = getSnapRadius() / this.zoom;
 
+    // Empty board: tap anywhere = center placement
+    if (!leftEp && !rightEp && this.activeEndpoint) {
+      return { end: 'right', value: null };
+    }
+
     if (leftEp && dist(worldX, worldY, leftEp.x, leftEp.y) < radius) return { end: 'left', value: leftEp.value };
     if (rightEp && dist(worldX, worldY, rightEp.x, rightEp.y) < radius) return { end: 'right', value: rightEp.value };
     return null;

public/js/modules/domino/scenes/game.js

@@ -508,6 +508,7 @@ function handleTileSelect(el, tile) {
     state.selectedTile = null;
     hand.clearSelection();
     board.clearActiveEndpoint();
+    updateUI(el);
     return;
   }
 
@@ -518,11 +519,11 @@ function handleTileSelect(el, tile) {
   // First tile on empty board → show center endpoint
   if (state.chain.length === 0) {
     board.setActiveEndpoint('both');
-    return;
+  } else {
+    board.setActiveEndpoint(playEnd);
   }
 
-  // Show which endpoints this tile can play on
-  board.setActiveEndpoint(playEnd);
+  updateUI(el);
 }
 
 function handleEndpointTap(el, hit) {