Enatega Admin-Dashboard + Customer: Ensure Consistent Naming for "Voucher" and "Coupons"

Issue:
The terms "Voucher" and "Coupons" are used interchangeably in the system, leading to inconsistency and potential confusion for users.

Impact:

Users may not clearly understand whether "Voucher" and "Coupons" refer to the same feature or different functionalities.
Inconsistent naming can create confusion in the UI, documentation, and communication.
It may affect API responses, database fields, or reports if both terms are used inconsistently in different places.

Recommendation:

Choose a single, consistent term: either "Voucher" or "Coupon."
Update all instances of the term across the UI, API, documentation, and database schema.
Ensure consistency in user-facing messages, buttons, forms, and reports.
Communicate the change to relevant teams to maintain uniformity in future development.

No files, tests, or entry points are named. First inventory the terms across the UI, API, documentation, database schema, messages, forms, and reports, then confirm the canonical term with maintainers; done means the chosen term is used consistently everywhere identified.

Written by the indexing model from the issue text.