feat: add Yuheng ticket bind, trial SMS off, shared bindings

Ship ticket-exchange and bind/policy for Z13, keep trial binds SMS-free, allow shared company bindings, and align SyncPage plus sync docs.

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/etc/platform.yaml

@@ -19,10 +19,12 @@ Auth:
   RequirePhoneBound: false
 
 SMS:
-  Provider: dev
+  Provider: off
   CodeTTLSeconds: 300   # 短信验证码有效期（秒）
   ResendSeconds: 60
   # DevFixedCode: "123456"
+  # 试运行未接短信平台：false；正式接入后改为 true，且 Provider 勿用 off
+  RequireForBind: false
 
 # 外公司部署：每次续费/延期生成独立签名文件（目录非固定单文件）
 License:
@@ -39,6 +41,13 @@ License:
 Agent:
   CapsuleSecret: "dev-agent-capsule-secret"
   RegisterSecret: "dev-only-change-me"
+  # 仅宇恒：HMAC 凭票免登录（生产务必换 Secret，并与宇恒后端共享）
+  YuhengTicket:
+    Enabled: true
+    Secret: "dev-yuheng-ticket-secret-change-me"
+    Issuer: yuheng
+    Audience: aijianzhan
+    MaxAgeSec: 120
 
 Storage:
   Driver: local