Feature: Dashboard tab with message counts per queue/subscription

[RaoulJacobs]

Summary

A new Dashboard tab (default selected on startup) showing all queues and topic subscriptions in a single DataGridView with their live message counts.

Motivation

Currently you have to click each queue/subscription individually to see its message counts. With a large namespace this is very slow. A dashboard gives an instant overview of the entire namespace health.

Behavior

• Dashboard tab as the default tab in the main TabControl
• DataGridView with columns: Name, Type (Queue/Subscription), Active, Dead Letter, Scheduled, Total
• Topics are expanded to their subscriptions (topics themselves hold no messages)
• Rows with Dead Letter > 0 highlighted in light red
• Refresh button — async reload without UI freeze
• Auto-refresh — checkbox + interval selector (30s / 60s / 5min)
• Clicking a dashboard row syncs the TreeView selection (right panel updates)
• Ctrl+C / right-click → copy row as TSV or copy name

Implementation

Implemented in our fork tailormade-eu/ServiceBusExplorer on top of upstream HEAD (d71dc35).

New file: src/ServiceBusExplorer/Controls/DashboardControl.cs + wiring in MainForm.cs.

Question

Is this a feature you'd accept a PR for?

[SeanFeldman]

I think this could be nice.
@RaoulJacobs, could you provide screenshots/vids of what the experience will look like? Thank you.

[RaoulJacobs]

Demo included in #861 — same recording covers both features.

[SeanFeldman]

This looks good. If you raise a PR, we'll review it. Thank you.