Client quick actions

A client screen carries a set of actions for the things staff do without opening a computer. Add credit puts a balance on the account. Send password reset triggers the WHMCS reset email, so the customer gets the usual link to set a new password. The app never sees or sets the password itself, and the action is greyed out if the client has no email on file. Add a note appends a short, timestamped line to that account admin notes, staff only, for the spoke-to-them-awaiting-docs kind of remark. Email overdue invoices re-sends the reminder for each unpaid, overdue invoice. Closing an account is reversible by reactivating; deleting a client is deliberately left to the admin area, as is anything that moves real money.