Create Admin Dashboard for Detecting Suspicious Account Registration Activity
#### Summary
Implement a new admin dashboard in `accounts.eclipse.org` that highlights potentially suspicious account registration patterns. The goal is to provide visibility into registration anomalies that may indicate spam, bot activity, abuse, or coordinated account creation attempts.
This initial implementation should focus on simple, actionable signals that can be expanded upon over time.
#### Motivation
We occasionally observe waves of account registrations that appear suspicious. Currently, identifying these patterns requires manual investigation and database queries.
Providing an administrative dashboard with basic anomaly detection will:
* Improve visibility into registration activity.
* Help identify spam campaigns earlier.
* Reduce manual investigation effort.
* Establish a foundation for more advanced detection capabilities in the future.
#### Proposed Initial Scope
Create an admin-only dashboard that displays anomaly indicators based on recent account creation activity.
#### **UI Mockup**
**Summary**
- Accounts created (last hour): 123
- Accounts created (last 24h): 2,341
**Top Domains - Last Hour**
* example-spam.com: 50
* suspicious.net: 37
* gmail.com: 22
**Note:** the top domains could link to a page like this: https://accounts.eclipse.org/admin/people?user=%40example-spam.com&status=All&role=All&permission=All
/cc @cguindon
issue