(feat/dns) DNS Resolution errors should be a 200

[nickscamara]

DNS Resolution errors should be a 200 with a success flag = false.

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Summary by cubic

DNS resolution errors in the v1/v2 scrape endpoints now return 200 with success: false. We also bill 1 credit for these cases and set tracing status_code to 200.

• New Features
  • v1/v2 scrape controllers return 200 with success:false, code, and error for SCRAPE_DNS_RESOLUTION_ERROR; spans record scrape.status_code=200.
  • Billing charges 1 credit on DNS resolution errors; worker forwards the error to billing.

^{Written for commit 9f6daa1. Summary will update automatically on new commits.}

[cubic-dev-ai]

No issues found across 4 files