Ability to add metadata via dropdown

🔍 Problem Statement

Admins need to attach structured metadata (e.g. department, campaign source, region) to customer or subscription records, but the current metadata input only supports free-text key-value pairs. This leads to inconsistent values, typos, and unreliable filtering or reporting.

💡 User Story

As a Pelcro admin, I want to add metadata values via a dropdown of predefined options, so that metadata is consistent, typo-free, and reliably filterable across reports and segments.

🎯 Definition of Done (DoD)

A feature is done when:

✔️ Given a metadata field configured with predefined dropdown options, when an admin adds metadata to a customer or subscription, then they can select from the predefined list and the saved value matches exactly — enabling reliable filtering and reporting.