Add XLParser demo solution

[aliakseiredzko]

[Copilot]

Pull Request Overview

This PR adds a complete XLParser demo solution, implementing a web application for parsing and visualizing Excel formulas using the Ivy framework.

• Creates a new Visual Studio solution with project configuration for XLParser demonstration
• Implements formula parsing services to process Excel formulas and extract token information
• Builds an interactive web UI that allows users to input formulas and explore the parse tree with color-coded tokens

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
xlparser/XLParserDemo.sln	Visual Studio solution file with project configuration
xlparser/XLParserDemo.csproj	Project file with .NET 9.0 target and package dependencies
xlparser/Services/ParseTreeNodeInfo.cs	Data models for parse tree nodes and metadata
xlparser/Services/FormulaParser.cs	Core parsing logic and tree traversal functionality
xlparser/README.md	Documentation for running and deploying the application
xlparser/Program.cs	Application entry point with server configuration
xlparser/GlobalUsings.cs	Global using statements for the project
xlparser/Apps/XLParserApp.cs	Main UI application with formula parsing and visualization
xlparser/.gitignore	Git ignore file for build artifacts and IDE files

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[rorychatt]

Make it the default app that opens. (edit program cs)

otherwise awesome job!

[aliakseiredzko]

@rorychatt done