feat: 完成 M2 mosh（LAN + tsnet 端到端验证）

- mosh(blinksh/ios C++)+protobuf-lite 交叉编译为 MoshCore.xcframework
  （CommonCrypto 后端、含 arm64 模拟器 slice；绕 autotools 用 CMake 直编 + 手写 config.h）
- tsnet 桥新增 UDP relay（StartMoshRelay：loopback↔tsnet.Dial 逐包搬运）
- MoshSession（pipe↔FILE*/pthread/SIGWINCH）+ MoshConnectScanner（TXCore，+4 单测=39）
- SSHTerminalModel 编排：SSH 引导 mosh-server→解析 MOSH CONNECT→relay→mosh 接管
- LAN 直连 + mosh-over-tsnet 均端到端验证通过，R1(tsnet UDP 数据报语义) 证伪

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vendor/protobuf/examples/add_person.py

@@ -0,0 +1,63 @@
+#! /usr/bin/env python
+
+# See README.txt for information and build instructions.
+
+import addressbook_pb2
+import sys
+
+try:
+  raw_input          # Python 2
+except NameError:
+  raw_input = input  # Python 3
+
+
+# This function fills in a Person message based on user input.
+def PromptForAddress(person):
+  person.id = int(raw_input("Enter person ID number: "))
+  person.name = raw_input("Enter name: ")
+
+  email = raw_input("Enter email address (blank for none): ")
+  if email != "":
+    person.email = email
+
+  while True:
+    number = raw_input("Enter a phone number (or leave blank to finish): ")
+    if number == "":
+      break
+
+    phone_number = person.phones.add()
+    phone_number.number = number
+
+    type = raw_input("Is this a mobile, home, or work phone? ")
+    if type == "mobile":
+      phone_number.type = addressbook_pb2.Person.MOBILE
+    elif type == "home":
+      phone_number.type = addressbook_pb2.Person.HOME
+    elif type == "work":
+      phone_number.type = addressbook_pb2.Person.WORK
+    else:
+      print("Unknown phone type; leaving as default value.")
+
+
+# Main procedure:  Reads the entire address book from a file,
+#   adds one person based on user input, then writes it back out to the same
+#   file.
+if len(sys.argv) != 2:
+  print("Usage:", sys.argv[0], "ADDRESS_BOOK_FILE")
+  sys.exit(-1)
+
+address_book = addressbook_pb2.AddressBook()
+
+# Read the existing address book.
+try:
+  with open(sys.argv[1], "rb") as f:
+    address_book.ParseFromString(f.read())
+except IOError:
+  print(sys.argv[1] + ": File not found.  Creating a new file.")
+
+# Add an address.
+PromptForAddress(address_book.people.add())
+
+# Write the new address book back to disk.
+with open(sys.argv[1], "wb") as f:
+  f.write(address_book.SerializeToString())