## Description
Implements real-time company auto-association for contacts based on
email domains. This is **Part 2** of the company model production
rollout (CW-5726).
**Task:**
- When a contact is created with a business email, automatically create
and associate a company from the email domain
- When a contact is updated with an email for the first time (email was
previously nil), associate with a company
- Preserve existing company associations when email changes to avoid
user confusion
- Skip free email providers and disposable domains
**Dependencies:**
⚠️ Requires PR #12657 (Part 1: Backfill migration) to be merged first
**Linear ticket:**
[CW-5726](https://linear.app/chatwoot/issue/CW-5726/company-model-setting-it-up-on-production)
## Type of change
- [x] New feature (non-breaking change which adds functionality)
## How Has This Been Tested?
- Service specs: Tests business email detection, company creation,
association logic, edge cases (existing companies, free emails, nil
emails)
- Integration specs: Tests full callback flow for contact create/update
scenarios
- All tests passing: 10 examples, 0 failures
- RuboCop: 0 offenses
## Checklist:
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules (PR #12657 pending)
---------
Co-authored-by: Sojan Jose <sojan@pepalo.com>