Webhook notifications for analytics milestones

[Manak-hash]

Problem

No way to get notified when you hit traffic milestones (100 clicks, 1000 views, etc.). You have to manually check the dashboard.

Proposed solution

Add optional webhook configuration in Settings:

• Webhook URL field
• Configurable thresholds (e.g., notify every 100 clicks, every 1000 views)
• Fires a POST request with JSON payload when threshold is hit
• Works with Discord/Slack webhooks

Acceptance criteria

• Webhook URL configurable in settings
• Threshold-based notifications fire correctly
• Supports Discord/Slack webhook format