Add LiNo protocol server mode (LINO API)

[konard]

🚀 Feature: LiNo Protocol Server Mode (LINO API)

This PR implements a WebSocket server mode for the link-cli tool, enabling remote execution of LiNo queries through a RESTful API.

📋 Issue Reference

Closes #30

✨ Features Added

🖥️ Server Mode Options

• --server: Start WebSocket server mode
• --port PORT (alias -p): Specify listening port (default: 8080)

🌐 WebSocket API

• Endpoint: ws://localhost:PORT/ws
• Input: LiNo query as plain text
• Output: Structured JSON response with query results

📊 JSON Response Format

{
  "query": "() ((1 1))",
  "changes": [
    {
      "before": "",
      "after": "(1: 1 1)"
    }
  ],
  "links": [
    "(1: 1 1)"
  ]
}

💡 Usage Examples

Start server on default port:

clink --server

Start server on custom port with database:

clink --server --port 3000 --db mydata.links

JavaScript client example:

const ws = new WebSocket('ws://localhost:8080/ws');
ws.onopen = () => ws.send('() ((1 1))'); // Create link
ws.onmessage = (event) => {
    const response = JSON.parse(event.data);
    console.log(response.changes, response.links);
};

🔧 Technical Implementation

• ASP.NET Core Minimal APIs for lightweight WebSocket server
• Full backward compatibility - existing CLI functionality unchanged
• Concurrent query processing with proper error handling
• InvocationContext pattern to handle 10+ command-line parameters
• Dependency injection for proper resource management

🧪 Testing

• Comprehensive unit tests for WebSocket functionality
• Integration tests for CLI parameter handling
• Error handling tests for malformed queries
• Multi-client connection tests

📚 Documentation

• Updated README with complete API documentation
• Added JavaScript client examples
• Updated developer section with server mode examples
• Included troubleshooting and usage patterns

⚡ Performance & Reliability

• Efficient WebSocket handling with proper connection lifecycle
• Async/await patterns throughout for non-blocking operations
• Graceful error handling with structured error responses
• Resource cleanup on connection close

🔄 Version & Compatibility

• Version bumped to 2.3.0 (new major functionality)
• Full backward compatibility maintained
• No breaking changes to existing CLI interface

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🎯 Ready for Review

This PR is now complete and ready for review. All tests pass, documentation is updated, and the implementation follows established patterns in the codebase.

🤖 Generated with Claude Code