Add Windows Package Manager submission documentation and manifest templates

[Copilot]

Provides documentation and manifest templates for submitting winget-tui to the microsoft/winget-pkgs repository.

Documentation

• WINGET_SUBMISSION.md - Complete submission workflow: manifest generation via wingetcreate, directory structure, validation, PR process, multi-arch support
• WINGET_QUICKSTART.md - Command reference for common operations
• manifests/README.md - Template usage and validation instructions

Manifest Templates

Three YAML files in manifests/example/ following manifest schema 1.6.0:

# Shanselman.WingetTUI.installer.yaml
InstallerType: portable
Commands: [winget-tui]
Installers:
  - Architecture: x64
    InstallerUrl: https://github.com/shanselman/winget-tui/releases/download/v0.1.3/winget-tui-x64.exe
  - Architecture: arm64
    InstallerUrl: https://github.com/shanselman/winget-tui/releases/download/v0.1.3/winget-tui-arm64.exe

Includes version manifest and locale files with package metadata, tags, and URLs. SHA256 hashes left as placeholders for actual submission.

README Updates

Added installation section with winget command preview and links to submission documentation.

Original prompt

How do I add this to Winget

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✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[shanselman]

Closing stale draft — winget submission docs can be revisited later.