Update notes on a posted transaction

You can now edit or clear the note attached to any existing transaction via the new PATCH/api/v1/transaction/:transactionId endpoint.

What’s new

• Partial‑update method – Send a PATCH request with a JSON body:
  JSON

  {
    "note": "Optional free‑form text up to 5 000 characters"   // null or "" clears the note
  }

• Immediate response – The call returns the full Transaction object, reflecting the new or cleared note.
• Scope‑controlled – Requests must be authenticated with an API token that includes the updateTransactions scope (write permission).

Validation rules

• Notes longer than 5 000 characters, or strings containing only whitespace, return 400 with an explanatory error.
• Transactions outside the token’s organisation, or tokens missing the required scope, return 403.

Use this endpoint to keep transaction metadata current without re‑posting the entire payment object.