Describe the bug
In loki-canary, the -streamvalue flag defaults to "stdout" even when the -push flag is set to true. This is misleading because when push=true, logs are not written to stdout but are instead pushed directly to the Loki HTTP endpoint. As a result, the stream label shown in queries can be confusing, showing "stdout" even though stdout is not used.

To Reproduce
Steps to reproduce the behavior:

1. Start loki-canary with -push=true and without specifying -streamvalue
2. Observe that the stream label is set to "stdout" despite logs being pushed via HTTP
3. Query logs in Loki using {stream="stdout"} and note the inconsistency in labeling

Expected behavior
If the -streamvalue flag is not explicitly provided:

• When -push=true, the default value of streamvalue should be "push" to reflect that logs are being sent via HTTP
• When -push=false, the default can remain "stdout"

This would make the labeling more accurate and intuitive when querying logs.

Environment:

• Infrastructure: Kubernetes
• Deployment tool: Helm

Screenshots, Promtail config, or terminal output
N/A — this is a behavioral issue visible in log labels and flag defaults

Additional context
I plan to submit a PR to address this issue shortly.