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/build_files_updated_unittest.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+# This script verifies that BUILD files and cmake files are in sync with src/Makefile.am
+
+set -eo pipefail
+
+if [ "$(uname)" != "Linux" ]; then
+  echo "build_files_updated_unittest only supported on Linux. Skipping..."
+  exit 0
+fi
+
+# Keep in sync with files needed by update_file_lists.sh
+generated_files=(
+  "BUILD"
+  "cmake/extract_includes.bat.in"
+  "cmake/libprotobuf-lite.cmake"
+  "cmake/libprotobuf.cmake"
+  "cmake/libprotoc.cmake"
+  "cmake/tests.cmake"
+  "src/Makefile.am"
+)
+
+# If we're running in Bazel, use the Bazel-provided temp-dir.
+if [ -n "${TEST_TMPDIR}" ]; then
+  # Env-var TEST_TMPDIR is set, assume that this is Bazel.
+  # Bazel may have opinions whether we are allowed to delete TEST_TMPDIR.
+  test_root="${TEST_TMPDIR}/build_files_updated_unittest"
+  mkdir "${test_root}"
+else
+  # Seems like we're not executed by Bazel.
+  test_root=$(mktemp -d)
+fi
+
+# From now on, fail if there are any unbound variables.
+set -u
+
+# Remove artifacts after test is finished.
+function cleanup {
+  rm -rf "${test_root}"
+}
+trap cleanup EXIT
+
+# Create golden dir and add snapshot of current state.
+golden_dir="${test_root}/golden"
+mkdir -p "${golden_dir}/cmake" "${golden_dir}/src"
+for file in ${generated_files[@]}; do
+  cp "${file}" "${golden_dir}/${file}"
+done
+
+# Create test dir, copy current state into it, and execute update script.
+test_dir="${test_root}/test"
+cp -R "${golden_dir}" "${test_dir}"
+
+cp "update_file_lists.sh" "${test_dir}/update_file_lists.sh"
+chmod +x "${test_dir}/update_file_lists.sh"
+cd "${test_root}/test"
+bash "${test_dir}/update_file_lists.sh"
+
+# Test whether there are any differences
+for file in ${generated_files[@]}; do
+  diff -du "${golden_dir}/${file}" "${test_dir}/${file}"
+done