Extract each Gitea tool builder into its own top-level function:
- _build_list_issues_tool(base_url, token, owner, repo)
- _build_create_issue_tool(base_url, token, owner, repo)
- _build_read_issue_tool(base_url, token, owner, repo)
_build_gitea_tools() is now 12 lines (was 137) — just assembles the
three helpers with shared connection params.
Fixes#1134
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>