feat: "WiFi Health Score" — your router's report card, always visible

[ajithakdev]

Summary

Create an overall "WiFi Health Score" (0–100) that combines all metrics into a single number that anyone can understand, displayed prominently in the popup, side panel, and toolbar badge.

The Score

📶 WiFi Health: 87/100 — Great!

Weighted formula:

• Download speed vs plan: 25%
• Upload speed vs plan: 15%
• Ping/latency: 20%
• Jitter (stability): 15%
• Packet loss: 15%
• Bufferbloat grade: 10%

Score ranges

Score	Label	Emoji	Meaning
90-100	Excellent	🚀	Perfect for everything
70-89	Great	🟢	Good for streaming, calls, gaming
50-69	Okay	🟡	Browsing fine, calls may stutter
30-49	Poor	🟠	Basic browsing only
0-29	Critical	🔴	Barely usable, take action

Why a single score matters

• Non-technical users don't want 6 different metrics. They want ONE answer: "Is my WiFi good?"
• It's the equivalent of a credit score for your internet
• Shareable: "My WiFi score is 87, what's yours?" → organic growth
• Trackable over time: "My score dropped from 85 to 42 this month"
• ISP accountability: "My ISP's average score is 38/100"

Display locations

1. Popup hero area: Big number with emoji and label
2. Toolbar badge: Show score number (87) with color background
3. Side panel: Score with trend arrow (↑↓) vs last test
4. PDF report: Score on cover page
5. Share card: Prominent in shared results

Implementation

• New calculateHealthScore() function in quality.ts
• Normalize each metric to 0-100 scale, apply weights
• If ISP plan is configured, score includes plan delivery %
• If no plan configured, score uses absolute thresholds