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/monitor/pinger.go

@@ -115,6 +115,6 @@ func (p *Pinger) send(uuid, suffix, body string) error {
 		lastErr = fmt.Errorf("HTTP %d", resp.StatusCode)
 	}
 
-	p.logger.Printf("[WARN] Health ping failed after 3 attempts (%s): %v", uuid, lastErr)
+	p.logger.Printf("[WARN] [monitor] Health ping failed after 3 attempts (%s): %v", uuid, lastErr)
 	return nil // Never let ping failures affect the caller
 }