feat: 长辈模式（大字大按钮 + 偏好按账号隔离）+ 语音输入（按住说话 + 实时转写 + 后端代理 DashScope ASR + 患者端专用）+ 健康仪表盘背景渐变

backend/src/Health.WebApi/Endpoints/speech_endpoints.cs

@@ -0,0 +1,69 @@
+using System.Net.WebSockets;
+using System.Text.Json;
+using Health.Application.Speech;
+
+namespace Health.WebApi.Endpoints;
+
+public static class SpeechEndpoints
+{
+    public static void MapSpeechEndpoints(this WebApplication app)
+    {
+        app.Map("/api/speech/realtime", async (
+            HttpContext http,
+            IRealtimeSpeechRecognitionProxy proxy,
+            ILoggerFactory loggerFactory) =>
+        {
+            if (!http.WebSockets.IsWebSocketRequest)
+            {
+                http.Response.StatusCode = StatusCodes.Status400BadRequest;
+                await http.Response.WriteAsJsonAsync(new
+                {
+                    code = 40001,
+                    data = (object?)null,
+                    message = "该接口仅支持 WebSocket 连接",
+                });
+                return;
+            }
+
+            if (!proxy.IsConfigured)
+            {
+                http.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
+                await http.Response.WriteAsJsonAsync(new
+                {
+                    code = 50301,
+                    data = (object?)null,
+                    message = "实时语音识别服务尚未配置",
+                });
+                return;
+            }
+
+            using var socket = await http.WebSockets.AcceptWebSocketAsync();
+            try
+            {
+                await proxy.ProxyAsync(socket, http.RequestAborted);
+            }
+            catch (OperationCanceledException) when (http.RequestAborted.IsCancellationRequested)
+            {
+                // 客户端离开页面或断开网络。
+            }
+            catch (Exception ex)
+            {
+                loggerFactory.CreateLogger("SpeechEndpoints")
+                    .LogError(ex, "Realtime speech proxy failed");
+                if (socket.State == WebSocketState.Open)
+                {
+                    var payload = JsonSerializer.SerializeToUtf8Bytes(new
+                    {
+                        type = "error",
+                        message = "语音服务暂时不可用，请稍后重试",
+                    });
+                    await socket.SendAsync(
+                        payload,
+                        WebSocketMessageType.Text,
+                        true,
+                        CancellationToken.None);
+                }
+            }
+        }).RequireAuthorization(policy => policy.RequireRole("User"));
+    }
+}