feat(examples): add cross-platform native terminal I/O example for Linux, macOS, and Windows

[prateekbhujel]

Summary

This PR adds examples/terminal, a complete demonstration of how to build cross-platform native CLI and TUI applications using TypePHP's mixed C++/PHP programming capabilities (cpp-src + php-src).

Standard PHP CLI applications traditionally depend on executing external sub-processes (stty, Windows mode CON) or installing separate PHP extensions to query window dimensions, enable raw mode, or capture hidden passwords. When compiled into a standalone native binary with TypePHP (tpc -m bin), this implementation interacts directly with the operating system kernel and console APIs with zero external dependencies and zero zval boxing overhead.

What is included

1. Cross-Platform C++ Native Module (examples/terminal/cpp-src/terminal.cc):

   • Terminal Dimensions: POSIX ioctl(TIOCGWINSZ) on Linux & macOS; GetConsoleScreenBufferInfo on Windows.
   • Interactive TTY Detection: isatty on Unix; GetConsoleMode on Windows.
   • Raw Mode Input: Non-canonical raw input mode (termios on Unix; SetConsoleMode on Windows) with atexit automated cleanup to ensure the terminal state is safely restored even on unexpected exit.
   • Secret Password Input: In-process hidden input without echo, restoring terminal flags immediately upon completion.
   • Window Title: Sets terminal window title via OSC escape sequence (\033]0;...\007) on Unix and SetConsoleTitleW (UTF-8 to UTF-16) on Windows.
   • ANSI Color Support: Detects TERM and NO_COLOR environment variables.

2. PHP Stubs & Object-Oriented Wrapper (examples/terminal/php-src/Terminal.php):

   • Direct native function signatures (terminal_get_width(), terminal_get_height(), etc.) for TypePHP's compiler to resolve.
   • High-level Terminal class with helper methods (getSize(), enableRawMode(), disableRawMode(), readSecret(), setTitle(), colorize()).

3. Demonstration Entrypoint (examples/terminal/main.php):

   • Interactive CLI application demonstrating dimensions, secret password input, single-key instant capture in raw mode, and colored box drawing.

4. Bilingual Documentation (examples/terminal/README.md):

   • Clear setup, compilation, and usage guide in English and Simplified Chinese matching the repository conventions.

5. PHPUnit Test (phpunit/TerminalExampleTest.php):

   • Unit test suite verifying class constants, fallbacks, ANSI coloring, and cursor formatting.

Verification

• C++ Compilation: Compiled cleanly with clang++ -std=c++17 -Wall -Wextra against phpx.h and PHP headers (0 errors).
• PHP Syntax: Validated with php -l on all PHP files (0 syntax errors).
• PHPUnit Tests: Ran ./vendor/bin/phpunit phpunit/TerminalExampleTest.php (6 tests, 15 assertions passed 100% green).
• Clean diff: Purely additive (6 new files, 0 modified existing files, 0 regressions to existing compiler passes).