Add command line interface and Docker support for text cleanup functionality

[Copilot]

This PR implements a complete command line version of the text-cleanup tool with Docker containerization support, addressing the need for automated text processing workflows and server deployments.

Key Features Added

Command Line Interface

• Full CLI tool (bin/text-cleanup) with comprehensive argument parsing
• Multiple input/output modes: stdin/stdout, file-to-file, and in-place editing
• Unix-style integration: Works seamlessly with pipes and automation scripts
• Proper error handling with meaningful messages and exit codes

Modular Architecture

• Extracted core logic into reusable Node.js module (lib/text-cleaner.js)
• Shared functionality between web app and CLI versions
• Clean separation of concerns for maintainability

Docker Support

• Lightweight Alpine-based container for easy deployment
• Security best practices with non-root user execution
• Proper stdin/stdout handling for containerized text processing
• Ready for CI/CD pipelines and server deployments

Usage Examples

# Clean text from stdin
echo "**Bold** text with 'smart quotes'" | text-cleanup

# Process files
text-cleanup input.txt output.txt

# In-place editing  
text-cleanup --in-place document.txt

# Docker usage
echo "Messy text" | docker run --rm -i text-cleanup-cli

Technical Implementation

The implementation maintains 100% compatibility with the existing web application while adding powerful automation capabilities. The shared text cleaning logic ensures consistent behavior across both interfaces.

Package Updates:

• Added CLI executable entry in package.json
• Updated project metadata and file inclusions
• Enhanced documentation with comprehensive usage examples

Testing:
All functionality has been thoroughly tested including CLI operations, Docker containerization, and Node.js module integration.

Fixes #2.

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