Add explanatory comments for immediate flush behavior

Clarify why connection events and terminal errors are flushed immediately:
- Connection events: Must capture before connection closes
- Terminal errors: May lead to termination, preventing future flushes

Addresses review feedback on PR #320

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: samikshya-db

telemetry/aggregator.go

@@ -64,7 +64,8 @@ func (agg *metricsAggregator) recordMetric(ctx context.Context, metric *telemetr
 
 	switch metric.metricType {
 	case "connection":
-		// Emit connection events immediately
+		// Emit connection events immediately: connection lifecycle events must be captured
+		// before the connection closes, as we won't have another opportunity to flush
 		agg.batch = append(agg.batch, metric)
 		if len(agg.batch) >= agg.batchSize {
 			agg.flushUnlocked(ctx)
@@ -107,7 +108,8 @@ func (agg *metricsAggregator) recordMetric(ctx context.Context, metric *telemetr
 	case "error":
 		// Check if terminal error
 		if metric.errorType != "" && isTerminalError(&simpleError{msg: metric.errorType}) {
-			// Flush terminal errors immediately
+			// Flush terminal errors immediately: terminal errors often lead to connection
+			// termination. If we wait for the next batch/timer flush, this data may be lost
 			agg.batch = append(agg.batch, metric)
 			agg.flushUnlocked(ctx)
 		} else {