[ENHANCEMENT] Remove duplicate endpoint display, keep only in extension details with copy button

[BenGWeeks]

Problem

The WebSocket endpoint URL is currently displayed in two places:

1. In the main content area (left side) in its own card
2. In the extension details panel (right side)

This is redundant and takes up unnecessary space.

Proposed Solution

1. Remove the duplicate endpoint card from the main content area
2. Keep the endpoint display in the extension details panel (right side)
3. Add a copy button next to the endpoint in the extension details section for easy copying

Current State

The endpoint wss://{host}/nostrclient/api/v1/relay appears twice on the page.

Expected State

• Single endpoint display in the extension details panel
• Copy button for quick clipboard access
• Cleaner, less cluttered interface