Extract duplicate access control logic from multiple LiveView files into
a reusable AccessControl helper module.
**Changes:**
- NEW: lib/towerops_web/live/helpers/access_control.ex
- NEW: test/towerops_web/live/helpers/access_control_test.exs
- Refactor device_live/index.ex to use AccessControl.verify_site_access/2
and verify_device_access/2
- Refactor device_live/form.ex to use AccessControl.verify_device_access/2
- Refactor alert_live/index.ex to use AccessControl.verify_alert_access/2
- Refactor device_live/show.ex to use AccessControl.verify_device_access/2
- Remove unused Repo aliases from refactored files
**Benefits:**
- Reduces code duplication across 7+ locations
- Centralizes security-critical access checks
- Improves testability (helper module has >90% coverage)
- Consistent error handling across all LiveViews
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
