docs: document keyless feedback in the v2 API reference

[Max17190]

Why

Document optional, evidence-based feedback for keyless Search, Scrape, and Parse using the API contract in #4616.

Summary

• Describe the API invitation, job references, 24-hour window, retries, failure observations, and Parse retention.
• Document endpoint-specific observations, reason codes, evidence requirements, and request limits in OpenAPI.
• Preserve authenticated feedback and the separate Search Feedback endpoint.

Publish before enabling the API invitations publicly; they link to this page. MCP and CLI support can follow once the API and docs are available.

Test Plan

• Valid OpenAPI JSON and 861 schema parity cases against the API implementation.
• Extraction-hostile markdown and locale fixture checks pass.
• Published preview verified with a fresh Firecrawl scrape: invitation wording, visible keyless required fields, metadata locations, expiry, retry timing, and size limits.
• The repository-wide locale literal check has the same 14 translated-page failures on main. Mintlify validation has the same 12 missing-snippet warnings on main. None of those pages is changed here.
• Requested Cubic review; no Cubic check or review has been posted for this PR.

[mintlify]

Preview deployment for your docs. Learn more about Mintlify Previews.

Project	Status	Preview	Updated
firecrawl	🟢 Ready	View Preview	Oct 1, 2026, 4:51 PM

💡 Tip: Enable Automations to automatically generate PRs for you.

[Max17190]

@cubic-dev-ai review this PR. Review the full diff using firecrawl/firecrawl#4616 as the API contract, including optional invitation language, endpoint-specific evidence, the 24-hour window, and preservation of authenticated feedback.