enhance(report): add runner.log_report_level for the uploaded runner messages (#1310)

The runner's own messages between steps (not step output) were uploaded to the job log at `log.level`, so raising `log.level` for local debugging also changed what workflow authors see in Gitea, and lowering it hid messages from them.

Add `runner.log_report_level` to set that independently. Unset, it still follows `log.level`, so existing setups behave as before. An invalid value is rejected when the config loads.

Assisted-by: Codet
Assisted-by: Claude Code:claude-opus-5-5
Co-authored-by: silverwind <[email protected]>
Co-authored-by: silverwind <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1310
Co-authored-by: Lunny Xiao <[email protected]>

internal/pkg/config/config.example.yaml

@@ -76,6 +76,9 @@ runner:
   # 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
+  # The lowest severity of the runner's own messages (not step output) that are sent to the
+  # job log between steps: trace, debug, info, warn, error. Default if omitted: follow log.level.
+  #log_report_level: info
   # The interval for reporting task state (step status, timing) to the Gitea instance.
   # State is also reported on step transitions (start/stop) and after each log flush.
   #state_report_interval: 5s