Update RunCommand to write launch settings messages to stderr for MCP

[Luiz-Ossinho]

Reasoning behind the issue

• MCP guides often redirect logs to stderr so stdout stays “clean” for the protocol messages.
• The dotnet run command outputs launchSettings.json usage messages to stdout, which the MCP server reads as incoming messages.
• Unfortunately, the current RunCommand.cs prints Reporter.Output.WriteLine unconditionally to stdout; the user can’t easily redirect this via dotnet run without code changes.

The TryGetLaunchProfileSettingsIfNeeded method prints a message like:

Using launch settings from C:\path\to\Properties\launchSettings.json

directly via:

// RunCommand.cs, line 469
Reporter.Output.WriteLine(string.Format(CliCommandStrings.UsingLaunchSettingsFromMessage, launchSettingsPath));

If the project logs are being sent to stdout, VS Code (or any LSP client) can interpret that as a protocol message. MCP servers expect JSON-RPC messages on stdout, so any other output (like this “Using launch settings from …”) is considered a malformed message, triggering:

Failed to parse message: "Using launch settings from ...\Properties\launchSettings.json..."

This is only a warning — the server still works, but the message pollutes the LSP/JSON-RPC stream.

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