Switch release workflow and GoReleaser to Gitea-native

- .goreleaser.yml: replace release.github with release.gitea, add
  gitea_urls pointing to git.ezscale.cloud
- release.yaml: use GITEA_TOKEN (via secrets.RELEASE_TOKEN) instead of
  GITHUB_TOKEN, remove manual curl-based Gitea release step (GoReleaser
  handles it natively now)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.goreleaser.yml

@@ -50,13 +50,18 @@ signs:
       - "${artifact}"
 
 release:
-  github:
+  gitea:
     owner: EZSCALE
     name: terraform-provider-virtfusion
   extra_files:
     - glob: 'terraform-registry-manifest.json'
       name_template: '{{ .ProjectName }}_{{ .Version }}_manifest.json'
 
+gitea_urls:
+  api: https://git.ezscale.cloud/api/v1/
+  download: https://git.ezscale.cloud
+  skip_tls_verify: false
+
 changelog:
   sort: asc
   filters: