docs(swagger): restore gold @Router comments on platform APIs

backend/plugins/domain/system/plugin.go

@@ -56,9 +56,7 @@ func (p *Plugin) Apply(ctx *core.Context) error {
 	ctx.Router().GET("/api/healthz", func(c *gin.Context) {
 		c.JSON(http.StatusOK, gin.H{"status": "ok"})
 	})
-	ctx.Router().GET("/api/health", func(c *gin.Context) {
-		c.JSON(http.StatusOK, response.OKNil())
-	})
+	ctx.Router().GET("/api/health", Health)
 	ctx.Router().RegisterWhitelist("/api/health")
 
 	// 2. Public config
@@ -92,3 +90,14 @@ func (p *Plugin) Apply(ctx *core.Context) error {
 
 	return nil
 }
+
+// Health 健康检查
+// @Summary 健康检查
+// @Description 检查服务是否正常运行，可用于负载均衡存活探测
+// @Tags health
+// @Produce json
+// @Success 200 {object} response.Any{data=string} "服务正常"
+// @Router /api/health [get]
+func Health(c *gin.Context) {
+	c.JSON(http.StatusOK, response.OKNil())
+}