Migrate to GitHub as primary repository + fix v0.2.0 checksum (#1)

* ci: fix checksum for manually created GitHub release v0.2.0

The GitHub release was created manually with gh CLI, so the checksum
in metadata didn't match. This updates the checksum to match the actual
tarball on GitHub.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

* refactor: migrate to GitHub as primary repository

- Move release workflow from Gitea Actions to GitHub Actions
- Update checksum to match manually created GitHub v0.2.0 release
- Simplify workflow by removing Gitea-specific steps
- Use softprops/action-gh-release for easier release management

This eliminates the complexity of Gitea mirroring and the issues
with GH_TOKEN authentication in Gitea Actions.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Happy <yesreply@happy.engineering>

artifacthub-pkg.yml

@@ -30,5 +30,5 @@ maintainers:
 annotations:
   headlamp/plugin/archive-url: "https://github.com/cpfarhood/headlamp-polaris-plugin/releases/download/v0.2.0/headlamp-polaris-plugin-0.2.0.tar.gz"
   headlamp/plugin/version-compat: ">=0.26"
-  headlamp/plugin/archive-checksum: sha256:f2e81af7b9e200cda2791baca284b6b06f48f2d662a04e9ef5a9d421757e5963
+  headlamp/plugin/archive-checksum: sha256:c73a754ecbb5ecdefa1ba4c12365aca0131a4b161825d4849339bf2aa24090f2
   headlamp/plugin/distro-compat: in-cluster