ci: isolate S3 upload workspace

[yanghang8612]

Summary

• download release artifacts into a run- and attempt-specific directory under RUNNER_TEMP
• run permission restoration, packaging, and S3 upload from that isolated directory
• clean the temporary workspace with an always() step

Root cause

The self-hosted for-linux runner reuses its repository workspace. A root-owned github/ directory was recreated there before the upload job started, so the java-tron runner user could not extract solc-windows.exe. This caused actions/download-artifact to retry five times and fail before the S3 upload step.

Impact

The upload job no longer depends on the ownership or contents of the persistent repository workspace. Each workflow run attempt uses ${RUNNER_TEMP}/solidity-${GITHUB_RUN_ID}-${GITHUB_RUN_ATTEMPT} and removes it on success or failure.

This addresses the failure observed in https://github.com/tronprotocol/solidity/actions/runs/30004204683.

Validation

• parsed .github/workflows/build.yml successfully as YAML
• ran git diff --check
• ran actionlint with the repository's custom for-linux runner label ignored
• confirmed the commit changes only .github/workflows/build.yml

[github-actions]

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