- New core/api_call_tracker.py — centralized tracker with rolling 60s
timestamps (speedometer) and 24h minute-bucketed history (charts)
- Instrument all 9 service client rate_limited decorators to record
actual API calls with per-endpoint tracking for Spotify
- 1-second WebSocket push loop for real-time gauge updates
- Modern radial arc gauges with service brand colors, glowing active
arc, endpoint dot, 0/max scale labels, smooth CSS transitions
- Click any gauge to open detail modal with 24h call history chart
(Canvas 2D, HiDPI, gradient fill, grid lines, danger zone band)
- Spotify modal shows per-endpoint history lines with color legend
and live per-endpoint breakdown bars
- Rate limited state indicator — blinking red badge with countdown
timer appears on gauge card when Spotify ban is active
- REST endpoint GET /api/rate-monitor/history/<service> for chart data
- Responsive grid layout (5 cols desktop, 3 tablet, 2 phone)
