Fix execution log URL-only retrieval flag

[cursor]

Description

Expose return_download_url in the public harness_get input schema so execution_log callers can request a signed log URL without falling back to full log download/decompression. Added a regression proving URL-only mode returns download_url and does not call the content resolver.

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other

Checklist

• Tests pass
• Typecheck passes

Verification: pnpm build && pnpm docs:generate && pnpm typecheck && pnpm test && pnpm docs:check && git diff --check.

  

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