feat: add prestige system and skill upgrades with comprehensive documentation

src/components/game/tabs/StatsTab.tsx

@@ -169,13 +169,11 @@ export function StatsTab({
           <div className="flex justify-between text-sm">
             <span className="text-gray-400">Enchantment Power:</span>
             <span className="text-blue-300 font-[var(--font-mono)]">
-              {upgradeEffects && 'enchantPower' in upgradeEffects 
-                ? `${(upgradeEffects as Record<string, number>).enchantPower.toFixed(2)}×` 
-                : '1.0×'}
+              {upgradeEffects?.enchantmentPowerMultiplier?.toFixed(2) || '1.0'}×
             </span>
           </div>
           <p className="text-xs text-gray-500 mt-2">
-            Increases the power of all enchantments. Wired from Task 5 implementation.
+            Increases the power of all enchantments by {((upgradeEffects?.enchantmentPowerMultiplier || 1) - 1) * 100}%. Multiplier applied to all enchantment effects.
           </p>
         </CardContent>
       </Card>