feat: migrate from GitLab CI to Gitea Actions

- Update git remote to git.unbound.se
- Add Gitea workflows: ci.yaml, pre-commit.yaml, release.yaml, goreleaser.yaml
- Delete .gitlab-ci.yml
- Update Go module path to gitea.unbound.se/unboundsoftware/schemas
- Update all imports to new module path
- Update Docker registry to oci.unbound.se
- Update .goreleaser.yml for Gitea releases with internal cluster URL
- Remove GitLab CI linter from pre-commit config
- Use shared release workflow with tag_only for versioning

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.goreleaser.yml

@@ -1,6 +1,10 @@
 project_name: unbound-schemas
 version: 2
 
+gitea_urls:
+  api: http://gitea-http.gitea.svc.cluster.local:3000/api/v1
+  download: https://gitea.unbound.se
+
 env:
 - CGO_ENABLED=0
 
@@ -27,11 +31,6 @@ homebrew_casks:
     name: "Joakim Olsson"
     email: joakim@unbound.se
   homepage: "https://schemas.unbound.se/"
-  hooks:
-    post:
-      install: |
-        # replace foo with the actual binary name
-        system_command "/usr/bin/xattr", args: ["-dr", "com.apple.quarantine", "#{staged_path}/schemactl"]
 
 archives:
 - id: unbound-schemas