Add CLI binary interface with stdin pipeline support for Kitten TTS

[andkirby]

Summary

• Added complete command-line interface for Kitten TTS
• Implemented stdin pipeline support for text input
• Added executable kitten-tts binary script
• Created comprehensive CLI with all major features
• No changes in core files

Key Features Added

• Command-line interface with comprehensive argument parsing
• Stdin pipeline support - can read text from pipes (e.g., echo "text" | kitten-tts)
• Executable binary script for direct usage
• Audio fade-out with customizable duration (default: 0.2s)
• Text preprocessing - automatic dots suffix to prevent abrupt
  audio cutoff
• Multi-format audio output (WAV, FLAC, OGG support)
• Voice selection for all 8 available voices (expr-voice-2/m/f
  through expr-voice-5/m/f)
• Speech speed control with float values
• System audio playback across platforms (macOS, Linux, Windows)
• Comprehensive help documentation with usage examples

Files Changed

• kitten-tts - New executable wrapper script
• kittentts/cli.py - Complete CLI implementation with pipeline
  support. And system installs the binary by path venv/kitten-tts

Usage Examples

# Basic usage with argument
kitten-tts "Hello world"

# Pipeline usage (stdin)
echo "Hello world" | ./kitten-tts
cat file.txt | kitten-tts --output audio.wav

# With specific voice and fade-out
kitten-tts "Hello world" --voice expr-voice-2-f --fade-out 0.3

# Save to file with custom speed
kitten-tts "Hello world" --output hello.wav --speed 1.2

# List available voices
kitten-tts --list-voices