fix: show chess pieces (remove font-size:0) + correct Stockfish API endpoint /api/chess/move

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

api/game.php

@@ -61,7 +61,7 @@ switch ($action) {
         $wtime = $input['wtime'] ?? 60000;
         $btime = $input['btime'] ?? 60000;
 
-        $apiUrl = STOCKFISH_API . '/play';
+        $apiUrl = STOCKFISH_API . '/api/chess/move';
         $payload = json_encode([
             'bot_id' => $botId,
             'fen' => $fen,
@@ -85,7 +85,7 @@ switch ($action) {
 
         if ($httpCode === 200) {
             $data = json_decode($response, true);
-            echo json_encode(['move' => $data['move'] ?? null]);
+            echo json_encode(['move' => $data['best_move'] ?? null]);
         } else {
             http_response_code(502);
             echo json_encode(['error' => 'bot_unavailable', 'status' => $httpCode]);

public/css/chessboard.css

@@ -119,13 +119,15 @@
 .piece {
   width: 85%;
   height: 85%;
-  font-size: 0;
-  background-size: contain;
-  background-repeat: no-repeat;
-  background-position: center;
+  font-size: calc(min(10vw, 56px));
+  line-height: 1;
+  display: flex;
+  align-items: center;
+  justify-content: center;
   cursor: grab;
   z-index: 1;
-  transition: transform 0.15s var(--ease);
+  transition: transform 0.15s ease;
+  user-select: none;
 }
 
 .piece:active { cursor: grabbing; }
@@ -136,18 +138,6 @@
   transform: scale(1.1);
 }
 
-/* Piece images via CSS classes - using unicode */
-.piece-wK::before, .piece-wQ::before, .piece-wR::before,
-.piece-wB::before, .piece-wN::before, .piece-wP::before,
-.piece-bK::before, .piece-bQ::before, .piece-bR::before,
-.piece-bB::before, .piece-bN::before, .piece-bP::before {
-  font-size: calc(min(10vw, 56px));
-  line-height: 1;
-}
-
-.piece-wK { content: ''; }
-.piece-bK { content: ''; }
-
 /* Coordinate labels */
 .board-coords-file, .board-coords-rank {
   position: absolute;