Termux: build with make, install to $PREFIX, no nl_langinfo on Android

- bootstrap_termux.sh installs pkg-config/binutils, builds with make,
  runs the tests and installs into Termux's $PREFIX/bin.
- Makefile drops -lpthread on Android (pthreads are in bionic libc).
- TUI assumes UTF-8 on Android: nl_langinfo needs API 26, Termux
  targets 24. All sources compile for aarch64-linux-android24 (NDK 27).

README.md

@@ -118,8 +118,13 @@ API Key：TUI 里输入并按 provider 保存到配置目录的 `credentials`（
 ### Termux
 
 ```bash
-pkg install clang make cmake libcurl ncurses-ui-libs
-cmake -B build -DCST_BUILD_TUI=ON && cmake --build build
+# 一键：装依赖、克隆、编译、安装到 $PREFIX/bin
+curl -fsSL https://git.whcself.xyz/WHC/CST-agent/raw/branch/main/scripts/bootstrap_termux.sh | bash
+
+# 或手动
+pkg install git clang make pkg-config binutils libcurl ncurses
+git clone https://git.whcself.xyz/WHC/CST-agent.git && cd CST-agent
+make && make install      # 装到 Termux 的 $PREFIX/bin，之后任意目录运行 cst-agent
 # 可选：旁路 Unix busybox
 # ./scripts/build_third_party_mingw.sh busybox-unix
 ```