feat: 医生端Web后台 + SignalR实时问诊

- 新增 doctor_web/ React前端 (dashboard/患者/问诊/报告/随访)
- 后端新增 doctor_endpoints (14个医生API) + ConsultationHub (SignalR)
- Flutter端 SignalR 替换轮询实现实时聊天

health_app/pubspec.lock

@@ -209,6 +209,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.9.3+5"
+  fixnum:
+    dependency: transitive
+    description:
+      name: fixnum
+      sha256: b6dc7065e46c974bc7c5f143080a6764ec7a4be6da1285ececdc37be96de53be
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.1"
   fl_chart:
     dependency: "direct main"
     description:
@@ -448,6 +456,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.11.1"
+  message_pack_dart:
+    dependency: transitive
+    description:
+      name: message_pack_dart
+      sha256: "71b9f0ff60e5896e60b337960bb535380d7dba3297b457ac763ccae807385b59"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.1"
   meta:
     dependency: transitive
     description:
@@ -568,6 +584,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.0"
+  signalr_netcore:
+    dependency: "direct main"
+    description:
+      name: signalr_netcore
+      sha256: "8d59dc61284c5ff8aa27c4e3e802fcf782367f06cf42b39d5ded81680b72f8b8"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.4.4"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -637,6 +661,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.4.0"
+  sse:
+    dependency: transitive
+    description:
+      name: sse
+      sha256: fcc97470240bb37377f298e2bd816f09fd7216c07928641c0560719f50603643
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.1.8"
+  sse_channel:
+    dependency: transitive
+    description:
+      name: sse_channel
+      sha256: "9aad5d4eef63faf6ecdefb636c0f857bd6f74146d2196087dcf4b17ab5b49b1b"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.1.1"
   stack_trace:
     dependency: transitive
     description:
@@ -709,6 +749,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.6.12"
+  tuple:
+    dependency: transitive
+    description:
+      name: tuple
+      sha256: a97ce2013f240b2f3807bcbaf218765b6f301c3eff91092bcfa23a039e7dd151
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.2"
   typed_data:
     dependency: transitive
     description:
@@ -717,6 +765,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.4.0"
+  uuid:
+    dependency: transitive
+    description:
+      name: uuid
+      sha256: "1fef9e8e11e2991bb773070d4656b7bd5d850967a2456cfc83cf47925ba79489"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.5.3"
   vector_math:
     dependency: transitive
     description: