hermes - 💡(How to fix) Fix bug: oneshot exits 0 with empty final response [2 pull requests]

Summary

hermes -z / oneshot mode can exit with status 0 while emitting no final response text. For non-interactive foreground automation, an empty final response is not a usable successful result: callers cannot distinguish a completed answer from a silent no-op unless they add an external wrapper.

Expected behavior

If oneshot mode completes without a non-empty final response, it should fail closed with a nonzero exit code and a short stderr diagnostic. Successful runs with final text should continue to print only the final text to stdout and exit 0.

Observed behavior

In local foreground runs using --provider copilot --model gpt-5.5 -z <prompt>, the process exited 0, produced no stdout/final response text, and made no working-tree change. Downstream automation treated this as a command-level success until a separate manual diff/stdout check caught it.

Scope

This is about the -z command contract only. It should not add retries, queues, schedulers, daemons, controllers, or background behavior.