feat: 添加 SSE 测试接口（在线人数查询 + 手动广播事件）

src/main/java/com/webgame/webgamebackend/sse/SseController.java

@@ -1,15 +1,21 @@
 package com.webgame.webgamebackend.sse;
 
 import cn.dev33.satoken.stp.StpUtil;
+import com.alibaba.fastjson2.JSON;
+import com.webgame.webgamebackend.common.event.SseEvent;
+import com.webgame.webgamebackend.common.event.SseEventType;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.MediaType;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
 
 import java.io.IOException;
+import java.util.Map;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
@@ -76,4 +82,44 @@ public class SseController {
         log.info("[SSE] 新连接建立, userId={}, 当前在线={}", userId, connectionManager.getOnlineCount());
         return emitter;
     }
+
+    // ==================== 测试接口 ====================
+
+    /**
+     * 查看当前 SSE 在线连接数
+     *
+     * GET /sse/test/online
+     */
+    @GetMapping("/test/online")
+    public Map<String, Object> onlineCount() {
+        return Map.of("onlineCount", connectionManager.getOnlineCount());
+    }
+
+    /**
+     * 手动发送广播事件（测试用）
+     *
+     * POST /sse/test/broadcast
+     * Body: { "event": "room_created", "data": { "roomId": "test", ... } }
+     *
+     * event 可选值: room_created / room_updated / room_removed / kicked / game_started / balance_chg
+     */
+    @PostMapping("/test/broadcast")
+    public Map<String, Object> testBroadcast(@RequestBody Map<String, Object> body) {
+        String eventType = (String) body.get("event");
+        Object data = body.get("data");
+
+        if (eventType == null || data == null) {
+            return Map.of("success", false, "error", "event 和 data 字段为必填");
+        }
+
+        try {
+            SseEventType type = SseEventType.valueOf(eventType.toUpperCase());
+            SseEvent event = SseEvent.broadcast(type, JSON.toJSONString(data));
+            connectionManager.broadcast(event);
+            log.info("[SSE] 测试广播, type={}, data={}", eventType, JSON.toJSONString(data));
+            return Map.of("success", true, "eventType", eventType, "onlineCount", connectionManager.getOnlineCount());
+        } catch (IllegalArgumentException e) {
+            return Map.of("success", false, "error", "无效的事件类型: " + eventType);
+        }
+    }
 }