fix: count current mirror open issues for spam gate

[CaptainTimon]

Summary

• Keep mirror issue scoring bounded by the PR lookback window.
• Fetch the miner's current mirror issues separately and use that unbounded current-open count for the open-issue spam multiplier.
• Record the current mirror open issue count on evaluations even when no lookback issues are scoreable.

Close: #929

Related Issues

Type of Change

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

Testing

• Tests added/updated
• Manually tested

Validation performed:

• python3 -m py_compile gittensor/validator/issue_discovery/mirror_scan.py gittensor/classes.py tests/validator/issue_discovery/test_mirror_scan.py
• git diff --check

Note: pytest could not be run in this local environment because pytest and runtime dependencies such as bittensor are not installed.

Checklist

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

[CaptainTimon]

@adamdecaf Could you please review my PR?
Thanks!

[alpurkan17]

Good fix! Counting current mirror open issues directly addresses the spam gate logic. The approach correctly handles the edge case. Looks good to me.

[CaptainTimon]

@anderdc Could you please review my PR?
Thanks!

[anderdc]

Duplicate of #930 which is better scoped/implemented. Closing.