Prepare for nightly release packages

[JimBobSquarePants]

Prerequisites

• I have written a descriptive pull-request title
• I have verified that there are no overlapping pull-requests open
• I have verified that I am following the existing coding patterns and practice as demonstrated in the repository. These follow strict Stylecop rules 👮.
• I have provided test coverage for my change (where applicable)

Description

• Updates workflow to use improved caching of LFS artifacts
• Updates workflow to allow publishing of nightly builds.
• Updates submodule to include license key requirement.
• Adds various repository files to allow packaging

[Copilot]

Pull Request Overview

This PR prepares the PolygonClipper project for nightly release packages by enabling automated publishing workflows and improving repository infrastructure. The changes focus on setting up proper CI/CD pipelines for both nightly and tagged releases while adding standard GitHub repository files and improving build caching.

• Updates workflow files to enable automated package publishing to both feedz.io (nightly) and NuGet (tagged releases)
• Improves LFS caching strategy with deterministic key generation and cross-platform compatibility
• Adds standard GitHub repository files including issue templates, contributing guidelines, and PR templates

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/PolygonClipper/PolygonClipper.csproj	Adds MinVer configuration and corrects package icon path
shared-infrastructure	Updates submodule commit reference
README.md	Enhances README with proper branding, badges, and centered layout
PolygonClipper.sln	Adds GitHub repository files to solution structure
PolygonClipper.props	Corrects namespace reference from PolygonClipper to SixLabors.PolygonClipper
.github/workflows/code-coverage.yml	Improves LFS caching with platform-independent key generation
.github/workflows/build-and-test.yml	Adds WarmLFS job and enables Publish job for automated package deployment
.github/PULL_REQUEST_TEMPLATE.md	Adds standardized pull request template
.github/ISSUE_TEMPLATE/oss-bug-report.yml	Adds structured bug report template
.github/ISSUE_TEMPLATE/config.yml	Configures issue template routing
.github/FUNDING.yml	Adds funding information
.github/CONTRIBUTING.md	Adds comprehensive contributing guidelines

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}