refactor: 迁移彩票设置至 LotterySettings 服务

- 更新多个控制器和服务，使用 LotterySettings 服务获取彩票相关配置，如默认币种、开奖间隔、下注窗口等，提升代码一致性与可维护性。
- 移除 .env.example 中不再使用的配置项，建议通过后台管理进行设置。

app/Services/LotterySettings.php

@@ -13,6 +13,84 @@ use Illuminate\Support\Facades\Cache;
  */
 final class LotterySettings
 {
+    public static function defaultCurrency(): string
+    {
+        $fallback = (string) config('lottery.default_currency', 'NPR');
+        $value = self::get('currency.default_code', $fallback);
+
+        return strtoupper(substr(trim((string) $value), 0, 16));
+    }
+
+    public static function drawTimezone(): string
+    {
+        return (string) self::get('draw.timezone', (string) config('lottery.draw.timezone', 'UTC'));
+    }
+
+    public static function drawIntervalMinutes(): int
+    {
+        $fallback = (int) config('lottery.draw.interval_minutes', 5);
+
+        return max(1, min(1440, (int) self::get('draw.interval_minutes', $fallback)));
+    }
+
+    public static function drawBufferDrawsAhead(): int
+    {
+        $fallback = (int) config('lottery.draw.buffer_draws_ahead', 8);
+
+        return max(1, (int) self::get('draw.buffer_draws_ahead', $fallback));
+    }
+
+    public static function drawBettingWindowSeconds(): int
+    {
+        $fallback = (int) config('lottery.draw.betting_window_seconds', 270);
+
+        return max(10, (int) self::get('draw.betting_window_seconds', $fallback));
+    }
+
+    public static function drawCloseBeforeDrawSeconds(): int
+    {
+        $fallback = (int) config('lottery.draw.close_before_draw_seconds', 30);
+
+        return max(5, (int) self::get('draw.close_before_draw_seconds', $fallback));
+    }
+
+    public static function drawRequireManualReview(): bool
+    {
+        $fallback = (bool) config('lottery.draw.require_manual_review', true);
+
+        return (bool) self::get('draw.require_manual_review', $fallback);
+    }
+
+    public static function drawCooldownMinutes(): int
+    {
+        $fallback = (int) config('lottery.draw.cooldown_minutes', 15);
+
+        return max(0, (int) self::get('draw.cooldown_minutes', $fallback));
+    }
+
+    public static function currencyDisplayDecimals(): int
+    {
+        $fallback = (int) config('lottery.ui.format.currency.decimals', 2);
+
+        return max(0, min(12, (int) self::get('currency.display_decimals', $fallback)));
+    }
+
+    public static function currencyDecimalSeparator(): string
+    {
+        return (string) self::get(
+            'currency.decimal_separator',
+            (string) config('lottery.ui.format.currency.decimal_separator', '.')
+        );
+    }
+
+    public static function currencyThousandsSeparator(): string
+    {
+        return (string) self::get(
+            'currency.thousands_separator',
+            (string) config('lottery.ui.format.currency.thousands_separator', ',')
+        );
+    }
+
     public static function cacheTtlSeconds(): int
     {
         return max(5, (int) config('lottery.settings.cache_ttl_seconds', 60));