Conduct a comprehensive audit of all error messages and warnings within the Account Creation flow, and update them to consistently use Codex styling.
####Goals
Ensure all Account Creation errors and warnings use consistent Codex components and styling
[TBD] Reduce visual noise by consolidating multiple messages into a single, structured alert when appropriate
####Scope
- Username validation errors (unavailable, invalid format, TitleBlacklist, etc.)
- Password validation errors
- Password match validation errors
- Email-related warnings or errors
- [TBD] HCaptcha error messages
- Any pre- or post-submit validation messaging
####Details from previous audit spike:
{T414235}
> ==== Username
>
> If username is already in use (馃洃 error):
>> Username entered already in use. Please choose a different name.
>
> If starting with a lowercase letter (鈿狅笍 warning):
>> Your username will be adjusted to "<username with first letter uppercase>" due to technical restrictions.
>
> If the username is too long (and probably some other reasons) (馃洃 error):
>> You have not specified a valid username.
>
> ==== Password
> If password is too short (馃洃 error)::
>> Passwords must be at least 8 characters.
>
> If password is too long (馃洃 error):
>> Passwords cannot be longer than 4096 characters.
>
> If password is the username (馃洃 error):
>> Your password must not appear within your username.
>
> If password is too common (馃洃 error):
>> The password entered is in a list of very commonly used passwords. Please choose a more unique password.
>
> ==== Confirm password
> If the passwords do not match (馃洃 error):
>> The passwords you entered do not match.
>
> ==== Email
> If the email is not valid (馃洃 error):
>> The email address cannot be accepted as it appears to have an invalid format.
>> Please enter a well-formatted address or empty that field.
>
> If email is too long (馃洃 error):
>> Your email address should have at most 255 characters.
>
> As soon as the email field receives focus and when something is entered (鈿狅笍 warning):
>> Please look for an email from us to verify your address.
**Other errors to consider:**
(1) When a username matches the TitleBlacklist
(2) when a logged-in user creates a new account via Special:CreateLocalAccount page (details: https://phabricator.wikimedia.org/T414235#11809796)