## OVERVIEW
Repository layer for NAM with 13 repos using interface-driven design and GORM transactions.

## WHERE TO LOOK
- repository/ for all implementations
- Interface: {Entity}Repo, Constructor: New{Entity}Repo(db *gorm.DB)
- Transaction pattern: db.Transaction(func(tx *gorm.DB) error {...})
- Files: devices_repo.go, users_repo.go, tower_repo.go, olt_repo.go, etc.

## CONVENTIONS
- Interface naming: {Entity}Repo
- Constructor: New{Entity}Repo(db *gorm.DB) {Entity}Repo
- Return (data, error) pairs
- Use wrapped errors for context

## ANTI-PATTERNS
- Skip transactions for mutating operations
- Return nil error on failures
- Embed business logic in repos
- Instantiate DB connections inside repos