Inline field rules (shown on touch)
✗ Valid email is required
✗ An account with this email already exists
✗ Must be at least 6 characters
✗ Must contain 1 uppercase letter and 1 number
✗ Passwords do not match
Server-error toasts
An account with this email already exists
Signup failed — please check your details
Success toast (then redirect to /login)
Account created! You can now log in.
Real-time email check on focusout. Client-side validation fires
before any API call.