- Add mail.GetQuota() using doveadm quota get
- Fix UserWithQuota response struct
- Fix frontend NaN display with Unknown fallback
- Update field names to camelCase (usedQuota)
- Remove dots from character class (handled separately)
- Check username doesn't start/end with dot
- Check for no consecutive dots (..)
- Valid chars: a-zA-Z0-9!#$%&'*+-/=?^_`{|}~-
- Added gin-gonic v1.10.0 dependency
- Refactored router.go: clean route groups with middleware chains
- Refactored all handlers to use gin.Context instead of http.ResponseWriter/*http.Request
- Simplified response helpers (JSON, Error, Success, Created, NoContent)
- Clean auth middleware using Gin's c.Set() for context
- Cleaner route definitions with path parameters (e.g., /domains/:name/users/:id)
- Admin routes moved to /api/admin group with RequireAdmin middleware
