Docs: Flows v4 API — same actionTypeId / type / enum-operator gotchas as nodejs SDK

[DigitalMole81]

Cross-post of HubSpot/hubspot-api-nodejs#695 — the same four Flows v4 errors surface when scripting workflows from this Python SDK, and the error messages mislead in the same way. Reproducible payloads and fixes: https://www.elemra.com/learn/hubspot-flows-v4-api-errors

Summary of what to know before hitting POST /automation/v4/flows:

• Legacy actionTypeId: "0-13" returns HTTP 500. Use "0-63809083" (add) / "0-63863438" (remove).
• Top-level type field is required and must match objectTypeId (CONTACT_FLOW for 0-1, PLATFORM_FLOW for 0-3).
• ENUM properties reject IS_NOT_EQUAL_TO; use IS_NONE_OF with a single-element values array.
• Unified-events filter branches cannot nest — promote to top-level eventFilterBranches[] entries.

Same offer as on the nodejs issue: happy to open a PR against the SDK's error messages or docs if useful.

[DigitalMole81]

Reproduction gist for the four errors (curl snippets that trigger + fix each one): https://gist.github.com/DigitalMole81/040b75267ee98ab91964800affd19f7f