ci: move blacksmith jobs to owned runners

[haasonsaas]

Summary:

• removes remaining Blacksmith runner labels from this repo
• routes trusted CI to owned EvalOps runners while keeping fork-triggered public PRs off private runners where applicable

Test plan:

• actionlint -shellcheck= -pyflakes= .github/workflows/*.yml
• git diff --check
• rg -n -i "blacksmith" .github returns no usage

[socket-security]

No dependency changes detected. Learn more about Socket for GitHub.

👍 No dependency changes detected in pull request