fix(bitbucket): paginate remote-scopes API to return all repositories…

[bramhanandlingala]

Summary

The Bitbucket remote-scopes endpoint only returned the first 100 repos/workspaces — nextPageToken was always empty, so the UI had no way to load more.

Root Cause

• listBitbucketRepos / listBitbucketWorkspaces never set the nextPage return value, so nextPageToken was always "".
• The /repositories/{workspace} call's fields filter also excluded next, so Bitbucket wouldn't have returned it anyway.

Changes Made

• models/repo.go — added a Next field to WorkspaceResponse and ReposResponse to capture Bitbucket's next link.
• api/remote_api.go:
  • Added next to the fields filter so Bitbucket includes it in the response.
  • Set nextPage whenever resBody.Next != "", so the UI can request the following page.
• api/remote_api_test.go — tests for both the next-page and last-page cases.

Does this close any open issues?

Closes #8999

[bramhanandlingala]

@klesh
could you review and apprve this PR request