fixed a bug

ios/OralTrainer/Views/AuthView.swift

@@ -234,7 +234,7 @@ struct RegisterView: View {
                     .overlay(RoundedRectangle(cornerRadius: 8).stroke(Theme.border, lineWidth: 1))
 
                 fieldLabel("手机号")
-                TextField("选填", text: $phone)
+                TextField("请输入 11 位手机号", text: $phone)
                     .textFieldStyle(.plain)
                     .keyboardType(.phonePad)
                     .padding(12)
@@ -292,13 +292,18 @@ struct RegisterView: View {
         guard username.count >= 3 else { statusText = "用户名至少 3 个字符"; return }
         guard password.count >= 8 else { statusText = "密码至少 8 位"; return }
         guard !nickname.isEmpty else { statusText = "请填写姓名"; return }
+        let cleanedPhone = phone.trimmingCharacters(in: .whitespaces)
+        guard cleanedPhone.range(of: "^1[3-9]\\d{9}$", options: .regularExpression) != nil else {
+            statusText = "请输入有效的 11 位手机号"
+            return
+        }
 
         isLoading = true
         statusText = "注册中..."
         defer { isLoading = false }
         do {
             let session = try await AuthAPI.register(
-                username: username, password: password, nickname: nickname, phone: phone
+                username: username, password: password, nickname: nickname, phone: cleanedPhone
             )
             auth.saveSession(session)
             dismiss()