Trader: support multiple trading configurations at the same time

[konard]

Summary

• Implements support for multiple trading configurations running simultaneously
• Enables trading the same instrument on different broker accounts with different settings
• Allows testing different trading parameters at the same time
• Supports trading multiple instruments simultaneously
• Maintains backward compatibility with existing single configuration format

Key Features

• Multiple configurations: Define an array of trading configurations in MultiTradingConfiguration
• Named configurations: Each configuration has a unique name for identification in logs
• Independent API clients: Each configuration uses its own InvestApiClient instance
• Concurrent execution: All trading services run simultaneously as hosted services
• Backward compatibility: Existing single configuration files continue to work

Configuration Examples

Multiple Configurations

{
  "MultiTradingConfiguration": {
    "Configurations": [
      {
        "Name": "TMON_Account1",
        "InvestApiSettings": { "AccessToken": "...", "AppName": "..." },
        "TradingSettings": { "Ticker": "TMON@", "AccountIndex": 0, ... }
      },
      {
        "Name": "TMON_Account2", 
        "InvestApiSettings": { "AccessToken": "...", "AppName": "..." },
        "TradingSettings": { "Ticker": "TMON@", "AccountIndex": 1, ... }
      }
    ]
  }
}

Legacy Single Configuration (still supported)

{
  "InvestApiSettings": { "AccessToken": "...", "AppName": "..." },
  "TradingSettings": { "Ticker": "TMON@", ... }
}

Files Changed

• Program.cs: Updated to support both single and multiple configuration modes
• TradingService.cs: Enhanced with configuration name logging prefixes
• TradingConfiguration.cs: New wrapper classes for multiple configurations
• appsettings.MultipleConfigurations.json: Example configuration file
• README.MultipleConfigurations.md: Comprehensive documentation

Use Cases

1. Same instrument, different accounts: Trade TMON@ on Account 1 and Account 2 with different settings
2. Multiple instruments: Trade TMON@ and TRUR simultaneously
3. A/B testing: Test different trading parameters on the same instrument
4. Risk diversification: Spread trading across multiple broker accounts

Testing

• ✅ Builds successfully with no compilation errors
• ✅ Maintains backward compatibility with existing configurations
• ✅ Proper dependency injection for multiple service instances
• ✅ Clear logging with configuration name prefixes

🤖 Generated with Claude Code

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Resolves #194