Upload financial documents (PDF, PNG, JPEG, XLSX) with a statement_type and optional portfolio_id.

Supported file formats: .pdf, .xlsx, .png, .jpg, .jpeg

You can optionally specify source_firm_id to indicate the originating firm (by ID or name).

If the file fails validation (e.g. password-protected, corrupt, empty), a 422 response is returned with a specific error_code. See the 422 response schema for all possible codes.