fix(report): swap log timer defaults so maxLatencyTimer is effective

- Change log_report_interval default from 3s to 5s (periodic sweep)
- Change log_report_max_latency default from 5s to 3s (single-line guarantee)
- Reverse config validation to warn when maxLatency >= interval
- Add TestReporter_MaxLatencyTimer to verify single-line flush
- Add TestReporter_BatchSizeFlush to verify batch threshold flush
- Add TestReporter_StateNotifyFlush to verify step transition flush

internal/pkg/config/config.example.yaml

@@ -37,11 +37,13 @@ runner:
   # Set to 0 or same as fetch_interval to disable backoff.
   fetch_interval_max: 60s
   # The base interval for periodic log flush to the Gitea instance.
-  # Logs may be sent earlier if the buffer reaches log_report_batch_size.
-  log_report_interval: 3s
+  # Logs may be sent earlier if the buffer reaches log_report_batch_size
+  # or if log_report_max_latency expires after the first buffered row.
+  log_report_interval: 5s
   # The maximum time a log row can wait before being sent.
   # This ensures even a single log line appears on the frontend within this duration.
-  log_report_max_latency: 5s
+  # Must be less than log_report_interval to have any effect.
+  log_report_max_latency: 3s
   # Flush logs immediately when the buffer reaches this many rows.
   # This ensures bursty output (e.g., npm install) is delivered promptly.
   log_report_batch_size: 100