feat: 在 WalletBalanceController 中集成主站钱包余额获取功能

新增 HttpMainSiteWalletBalanceClient，用于在配置启用时获取主站钱包余额。
更新 WalletBalanceController：根据主站 API 返回结果新增 main_balance 与 main_balance_formatted 字段。
在 lottery.php 中新增钱包余额 API 路径配置项。
增强 WalletBalanceTest，验证在配置主站 API 后可正确获取 main_balance。

tests/Feature/WalletBalanceTest.php

@@ -5,11 +5,13 @@ use App\Lottery\ErrorCode;
 use App\Models\PlayerWallet;
 use Database\Seeders\CurrencySeeder;
 use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Http;
 
 uses(RefreshDatabase::class);
 
 beforeEach(function (): void {
     $this->seed(CurrencySeeder::class);
+    config(['lottery.main_site.wallet_api_url' => null]);
 });
 
 test('wallet balance creates lottery wallet row and returns zeros', function () {
@@ -55,6 +57,38 @@ test('wallet balance rejects illegal currency query', function () {
         ->assertJsonPath('code', ErrorCode::WalletInvalidCurrency->value);
 });
 
+test('wallet balance returns main_balance when main site wallet api is configured', function () {
+    config([
+        'lottery.main_site.wallet_api_url' => 'http://fake-main.test',
+        'lottery.main_site.wallet_balance_path' => '/wallet/balance',
+    ]);
+
+    Http::preventStrayRequests();
+    Http::fake([
+        'http://fake-main.test/wallet/balance*' => Http::response([
+            'success' => true,
+            'data' => [
+                'main_balance' => 499_900,
+                'currency_code' => 'NPR',
+            ],
+        ], 200),
+    ]);
+
+    $player = Player::query()->create([
+        'site_code' => 'main-site',
+        'site_player_id' => '10003',
+        'username' => null,
+        'nickname' => null,
+        'default_currency' => 'NPR',
+        'status' => 0,
+    ]);
+
+    $this->withHeader('Authorization', 'Bearer dev:'.$player->id)
+        ->getJson('/api/v1/wallet/balance')
+        ->assertOk()
+        ->assertJsonPath('data.main_balance', 499_900);
+});
+
 test('wallet balance rejects currency that is not configured or disabled', function () {
     $player = Player::query()->create([
         'site_code' => 'test',