Enhance project metadata for clarity and detail

[shibayan]

This pull request updates the NuGet package metadata in the Sharprompt.csproj file to improve discoverability and provide more accurate information about the package. The changes clarify the package's description, update links, and enhance search tags.

NuGet package metadata improvements:

• Updated the Description to better explain the features of the package, emphasizing input, selection, validation, and model binding.
• Added a PackageTitle property for clearer identification.
• Changed the PackageProjectUrl to point to the documentation site instead of the GitHub repository.
• Updated the PackageReleaseNotes to include a prefix and link to the release notes.
• Expanded PackageTags to include additional relevant keywords such as csharp, dotnet, model-binding, and validation for better searchability.

[Copilot]

Pull request overview

Updates NuGet package metadata for Sharprompt to improve discoverability and provide more accurate package details when published.

Changes:

• Expanded the package Description and added PackageTitle.
• Pointed PackageProjectUrl to the documentation site and improved PackageReleaseNotes text.
• Broadened PackageTags with additional search keywords.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.