ci: remove unused workflow integrations

[JOY (JOY)]

Summary

• remove the disabled inactive-issue workflow that never ran in the DOS fork
• remove the unconfigured S3 Playwright report publishing path
• always retain generated Playwright HTML reports as GitHub artifacts
• preserve GitHub Actions parallel steps

Root cause

Two actionlint findings came from obsolete integrations: actions/stale@v5 and aws-actions/configure-aws-credentials@v1. The stale workflow has been disabled for inactivity since 2023 and has no runs. The DOS repository has no AWS report variables or secrets. Across 193 Checks runs, S3 upload succeeded 0 times and was skipped in all 195 job attempts; AWS credential setup failed only in three old attempts before the workflow gained its AWS guard.

The remaining two local actionlint messages are confirmed false positives for GitHub parallel steps introduced on 2026-06-25. actionlint issue blockscout#693 and PR blockscout#694 track support for this syntax.

Validation

• git diff --check
• no remaining AWS, S3, stale-action, or upstream report-link references
• actionlint exits 0 when filtering only its known parallel-step parser message
• reviewer verified a real report run uploaded the GitHub artifact successfully while AWS and S3 were skipped
• full GitHub Actions CI will validate the native parallel syntax and Playwright artifact path