Show enrichment provider credits in CLI receipts

[developersdigest]

A successful firecrawl/enrich call can report 30 provider credits while the CLI prints Credits: 0, because the receipt only recognizes SQL's separately billed costs. Include enrichment's providerCredits in the existing separate-cost receipt field and displayed total, retaining the outer request's zero charge.

Incomplete or invalid enrichment cost reports are labeled as known credits, with a notice that additional costs may have been incurred. providerCostsComplete reflects completeness of the API's reported amounts, not independent confirmation of billing settlement. The change does not modify API responses, charge users or sum step costs a second time. Existing SQL and search receipt behavior remains intact.

Validation: all 28 receipt tests pass, TypeScript build passes, formatting and diff checks pass. The built formatter reproduces the reported case as Credits: 30 (0 outer request + 30 separately billed provider calls) without making a paid request.

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Summary by cubic

Fixes CLI receipts showing Credits: 0 after enrichment calls that report provider credits. Enrichment's providerCredits now count toward the separately billed total and displayed total, while the outer request stays at zero.

• Incomplete or invalid enrichment cost reports are labeled as known credits with a notice that additional costs may be incurred.
• providerCostsComplete reflects API-reported completeness, not billing confirmation.
• API responses, billing charges, and SQL/search receipt behavior are unchanged.

^{Written for commit a2151d4. Summary will update on new commits.}