Fix Gitea pipelines to use authenticated tea CLI without --login flag

Remove redundant --login librete flags from all gt-* pipeline tea commands since
authentication is already configured via tea logins. This simplifies the commands
and prevents potential authentication issues.

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

.wave/pipelines/gt-issue-research.yaml

@@ -27,7 +27,7 @@ steps:
         Parse the input to extract the repository and issue number.
         Use the tea CLI to fetch the issue:
 
-        tea issues list --repo <owner/repo> --login librete -o json -f index,title,body,labels,state,url --limit 50
+        tea issues list --repo <owner/repo> -o json -f index,title,body,labels,state,url --limit 50
 
         Then filter the JSON output for the issue matching the requested number.
 
@@ -224,7 +224,7 @@ steps:
            <markdown_content>
            COMMENT_EOF
 
-           tea comment <number> "$(cat /tmp/comment-body.md)" --repo <owner/repo> --login librete
+           tea comment <number> "$(cat /tmp/comment-body.md)" --repo <owner/repo>
 
         4. Add a footer to the comment:
            ---