Changes:
- Fix traffic graph to handle nil interface octets gracefully
- Add comprehensive tests for nil octets scenarios
- Fix agent polling query to support devices assigned directly to org (left join on sites)
- Fix test SNMP connection to inherit credentials from site/org
- Refactor agent_channel process_polling_result to reduce nesting (Credo)
- Add alias for JobCleanupTask in application.ex (Credo)
This fixes crashes when interface stats have nil octets and ensures
devices without a site assignment can be polled by agents.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>