fix: add missing board-legal and ludo-path-border to admin theme editor

These CSS variables were used in the game styles but weren't editable
via the admin theme customization page.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pages/admin-theme.php

@@ -187,6 +187,7 @@ const THEME_FIELDS = {
     { key:'board-last-move', label:'Last Move Highlight', type:'text', default:'rgba(255, 199, 40, 0.35)' },
     { key:'board-check', label:'Check Highlight', type:'text', default:'rgba(239, 68, 68, 0.55)' },
     { key:'board-premove', label:'Premove Highlight', type:'text', default:'rgba(21, 180, 240, 0.3)' },
+    { key:'board-legal', label:'Legal Move Dots', type:'text', default:'rgba(0, 0, 0, 0.18)' },
     { key:'board-highlight-green', label:'Highlight Green', type:'text', default:'rgba(21, 180, 90, 0.4)' },
     { key:'board-highlight-red', label:'Highlight Red', type:'text', default:'rgba(220, 50, 50, 0.4)' },
     { key:'board-highlight-yellow', label:'Highlight Yellow', type:'text', default:'rgba(220, 180, 30, 0.4)' },
@@ -259,6 +260,7 @@ const THEME_FIELDS = {
     { key:'ludo-board-bg', label:'Board Background', type:'color', default:'#1a2332' },
     { key:'ludo-path', label:'Path Cell Color', type:'color', default:'#f5f5f5' },
     { key:'ludo-safe', label:'Safe Position Color', type:'color', default:'#FFD54F' },
+    { key:'ludo-path-border', label:'Path Cell Border', type:'text', default:'rgba(0,0,0,0.1)' },
     { key:'ludo-home-p1', label:'Home Entrance P1', type:'text', default:'rgba(229,57,53,0.3)' },
     { key:'ludo-home-p2', label:'Home Entrance P2', type:'text', default:'rgba(67,160,71,0.3)' },
     { key:'ludo-home-p3', label:'Home Entrance P3', type:'text', default:'rgba(253,216,53,0.3)' },