fix: correct data fetching for groups, projects, commits and remove dead code

What does this MR do and why?

fix: correct data fetching for groups, projects, commits and remove dead code

• fix(groups): derive group membership from contributed_projects namespaces instead of /groups?membership=true which returns token owner's groups
• fix(projects): use /users/{id}/contributed_projects API directly for accurate contributed project count instead of inferring from push events
• fix(batch): remove commit-count filter that was incorrectly dropping valid contributed projects from the display
• fix(client): improve error reporting in safe_api_call_async with better logging for 401/403/404 errors and connection failures
• fix(commits): restore proper author matching with name/email/username validation to avoid cross-user commit pollution
• fix(env): fix malformed GITLAB_TOKEN format (leading space and quotes)
• chore: remove dead code - repro_timeout*.py, test_asyncio_patch.py, requirements.txt, batch_mode/client.py and its test file
• chore: remove nest_asyncio dependency (conflicts with aiohttp 3.11+)
• test: update test_misc_utils.py to match new groups/projects API endpoints