v0.1.6 - fix Gitea Release creation

Fixed

• Gitea/Forgejo: forge_tag_create reported a Release it never created. The adapter
  nested a release object inside the POST /tags body, but Gitea's CreateTagOption is
  {tag_name, target, message} — the extra key is not part of that schema, so the server
  dropped it silently and still answered 201, and the tool then echoed release: true
  off the request it had sent rather than off anything the server did. Verified against
  Gitea 1.27.0 through its own /swagger.v1.json. A Release is now its own
  POST /releases call, and the returned flag reflects what the server actually created.

Added

• forge_tag_create reports releaseUrl (Gitea/Forgejo), so a caller gets the Release
  address rather than having to guess it from the tag name.

Notes

• The regression test was itself the reason this survived: the Gitea mock read release
  off the POST /tags body, mirroring the adapter's assumption instead of the server's
  behaviour, so the false positive sailed through a green suite. The mock now models the
  real API and the assertion checks the separate call rather than the reported flag.