## Generate Branding Upload URL
Generates a pre-signed URL for uploading branding assets (logos, sidebar images) to the merchant's storage.
Returns an object containing the URL and the object key (which includes the timestamped filename).

## Endpoint signature

```http
POST https://api.reservepay.com/merchants/generate-branding-upload-url HTTP/1.1
Content-Type: application/json
Accept: application/json
Authorization: Bearer <token>

{
  filename: string,
  type: string,
  md5_hash: string,
  byte_size: number,
}
```

Returns: object

## Request arguments

### `filename` (string)

**Required**. The name of the file to be uploaded. Must include the file extension (e.g., 'logo.png').

### `type` (string)

**Required**. The type of branding image being uploaded.

Allowed values:

- `light_logo`
- `dark_logo`
- `sidebar_image`

### `md5_hash` (string)

**Required**. The MD5 hash of the file to be uploaded. This is used to verify the integrity of the file during upload.

### `byte_size` (number)

**Required**. The size of the file in bytes. This is used to validate the upload and ensure the file size matches the expected value.

## Response attributes

### `url` (string)

**Always present**. The upload URL where files can be uploaded.

### `upload_id` (string)

**Always present**. The ID of the upload session.

### `headers` (object)

**Always present**. The HTTP headers required for the upload request.

## Errors specific to this endpoint

### `INVALID_ARGUMENTS`

This error occurs when the request contains invalid or missing parameters.
Common cases include missing required fields, or values that don't match the
expected format or type.

### `NOT_FOUND`

This error occurs when the merchant branding is not found.

## Errors common to all endpoints

### `UNHANDLED_ERROR`

This error occurs when the server encounters an unexpected internal error that
it cannot handle gracefully. This typically happens due to bugs, infrastructure
issues, or edge cases that weren't anticipated during development.

### `INVALID_ARGUMENTS`

This error occurs when the request contains invalid or missing parameters.
Common cases include missing required fields, or values that don't match the
expected format or type.

### `BAD_VERSION`

This error occurs when making requests to an API version that does not exist.
This commonly happens when using an outdated SDK or when the API version
specified in the request URL is incorrect.