[BUG] Valid issues with successful merged PR is counted as closed instead of valid

[corevibe555]

Description

5 miner-authored issues on entrius/gittensor-ui were all closed via successfully merged PRs, but the issue discovery pipeline only credits 1 of them as solved — the other 4 are counted as closed (negative credibility) despite having a merged solving PR. This happens consistently across cycles, so it is not a transient API failure.

Affected issues:

entrius/gittensor-ui#151
entrius/gittensor-ui#196
entrius/gittensor-ui#197
entrius/gittensor-ui#199
entrius/gittensor-ui#199

All four were closed by merged PRs. Only one of the five is reflected in total_solved_issues; the rest land in total_closed_issues, dragging issue_credibility down and zeroing their discovery_earned_score.

Steps to Reproduce

1. Visit https://gittensor.io/miners/details?githubId=45244658&mode=issues
2. See Credibility section - 1 solved, 4 closed.

Expected Behavior

• All 5 issues should be counted as resolved.

Actual Behavior

• Only 1 of the 5 issues is counted toward total_solved_issues.

Additional Context

[corevibe555]

I think #434 also solved this problem