fix: standardize log prefixes, remove duplicates, add missing module tags

Second-pass logging cleanup: consistent [LEVEL] [module] format across
all 41 files. Remove stale prefixes ([CF], [SYNC], [SCHED], [API],
[STORAGE], [HEALTH], [ROLLBACK]). Remove 5 duplicate log lines. Gate
ungated DEBUG lines. Fix wrong log levels (restore start WARN→INFO).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/web/alerts.go

@@ -152,9 +152,6 @@ func (am *AlertManager) Refresh(report *monitor.HealthReport, cfg *config.Config
 	am.mu.Lock()
 	am.alerts = alerts
 	am.mu.Unlock()
-
-	am.logger.Printf("[DEBUG] AlertManager refreshed: %d alerts (%d error, %d warning)",
-		len(alerts), countLevel(alerts, "error"), countLevel(alerts, "warning"))
 }
 
 // GetAlerts returns a copy of the current alerts, optionally excluding specific IDs.