fix(cli): exit non-zero on logical issue command failures

[MkDev11]

Summary

• Return non-zero exit codes for logical failure branches in issue CLI admin/vote commands.
• Return non-zero exit codes for harvest failure outcomes (partial, failed/error, None, unexpected status).
• Add regression tests that assert these branches now exit non-zero.

Related Issues

Closes #706

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other (describe below)

Testing

• Tests added/updated
• Manually tested

Checklist

• Code follows project style guidelines
• Self-review completed
• Changes are documented (if applicable)