Add comprehensive metrics collection for production monitoring: - src/lib/metrics.ts: prom-client based metrics library with custom counters, gauges, and histograms for Garmin sync, email, and decision engine - GET /api/metrics: Prometheus-format endpoint for scraping - Integration into garmin-sync cron: sync duration, success/failure counts, active users gauge - Integration into email.ts: daily and warning email counters - Integration into decision-engine.ts: decision type counters Custom metrics implemented: - phaseflow_garmin_sync_total (counter with status label) - phaseflow_garmin_sync_duration_seconds (histogram) - phaseflow_email_sent_total (counter with type label) - phaseflow_decision_engine_calls_total (counter with decision label) - phaseflow_active_users (gauge) 33 new tests (18 library + 15 route), bringing total to 586 tests. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
119 KiB
119 KiB