Add HeicodeUsageCard between balance and subscription plans:
- 14-day usage sparkline from /api/user/heicode/usage
- Last 6 requests from /api/user/heicode/logs
Both endpoints come from the product-package §4 contract (mcp-server),
so the figures match what the desktop sidecar sees.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>