## Linear reference:
https://linear.app/chatwoot/issue/CW-4649/re-imagine-assignments
## Description
This PR introduces the foundation for Assignment V2 system by
implementing agent_capacity and their association with inboxes and
users.
## Type of change
- [ ] New feature (non-breaking change which adds functionality)
## How Has This Been Tested?
Test Coverage:
- Controller specs for assignment policies CRUD operations
- Enterprise-specific specs for balanced assignment order
- Model specs for community/enterprise separation
## Checklist:
- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules
---------
Co-authored-by: Pranav <pranav@chatwoot.com>
