[diagnose-skill local self-test 2]

diagnostic_id: a62bb1a5-6d92-4719-b6e3-0deead10a04b
### Summary
Self-test invocation against unreachable server URL.
### Frequency
once
### Severity
low
### Happier version
0.2.5-dev.97.1
### Platform
darwin
- OS: 25.3.0
### Deployment type
self-hosted
### Diagnostics
- Included: no
- Uploaded artifacts: 0