Add Copy to Clipboard Button for API Keys

🔍 Problem Statement

API keys displayed in the Pelcro dashboard cannot be copied with a single click. Admins must manually select the full key string, which is error-prone and wastes time — especially for long keys.

💡 User Story

As a Pelcro admin, I want a copy-to-clipboard button next to API keys, so that I can copy them instantly without manual selection errors.

🎯 Definition of Done (DoD)

A feature is done when:

✔️ Given an API key displayed in the dashboard, when an admin clicks the copy button, then the full key is copied to the clipboard and a visual confirmation is shown.