fix: display separately billed SQL provider credits

[developersdigest]

Executed firecrawl/sql responses report zero outer credits because their provider calls are charged separately. The CLI currently prints only that zero, hiding the nested reported cost.

Add separatelyBilledCredits to the CLI receipt and display the combined reported cost with an explicit outer/provider breakdown. Preserve creditsUsed as the outer charge, leave nested provider receipts intact, and only recognize successful firecrawl/sql result envelopes with finite non-negative costs. Ordinary provider payloads, previews, failures, and invalid costs are excluded.

Validation: 14 receipt tests and all 48 Alexandria CLI HTTP tests passed across focused runs (the new case rerun after correcting test JSON quoting); build, typecheck and git diff --check passed. No paid live calls.

Companion Exchange receipt fix: https://github.com/firecrawl/exchange/pull/708. This display also works with existing SQL results that have a null nested receipt.

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Summary by cubic

Fixes CLI receipt display so SQL provider calls billed separately no longer appear as zero total credits.

• Adds separatelyBilledCredits to the receipt and prints a combined total with an outer/provider breakdown.
• Keeps creditsUsed as the outer request charge and leaves nested provider receipts unchanged.
• Only successful firecrawl/sql result envelopes with finite non-negative costs are counted; other payloads, failures, and invalid costs are ignored, while valid costs are retained when mixed with invalid ones.

^{Written for commit b89b1d4. Summary will update on new commits.}

[cubic-dev-ai]

All reported issues were addressed across 3 files

<sub>Shadow auto-approve: would not auto-approve because issues were found.

Fix all with cubic | Re-trigger cubic</sub>

[cubic-dev-ai]

0 issues found across 2 files (changes from recent commits).

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

<sub>Shadow auto-approve: would auto-approve. Fixes CLI receipt display so separately billed SQL provider credits are shown with an outer/provider breakdown instead of a misleading zero. The change is display-only, narrowly scoped to receipt rendering, and covered by focused tests.

Re-trigger cubic</sub>