feat: Modem/router uptime tracking — "Your router hasn't been restarted in 47 days"

[ajithakdev]

Summary

Estimate how long the user's router has been running without a restart by tracking public IP changes and connection drops.

How it works

• Track the user's public IP (from Cloudflare Worker response) across tests
• When IP changes: likely router restart or ISP reassignment
• Track time since last IP change as "estimated router uptime"
• Correlate with quality trends

Display

🔄 Router Uptime: ~47 days since last restart
📉 Quality trend: Declining (-18 points)
💡 Tip: Routers perform best when restarted every 2-4 weeks

Why

• Most non-technical users never restart their router
• Long uptimes correlate with degraded performance (memory leaks, stale caches)
• Provides a concrete, actionable data point
• Combined with the "Router Reboot Reminder" feature, this creates a complete router health story

Privacy

• IP is only used for change detection, never stored in full
• Store only: hash of IP + timestamp of last change
• All processing is local