Define a Cloudinary structured metadata field and apply it alongside free-form tags to assets via the Admin API

Steps

1. Use the Admin API's metadata fields endpoint to create a structured metadata field definition (specifying type, e.g. string/enum/date, and any validation or datasource list of allowed values) at the account level
2. Distinguish structured metadata (global field definitions applied consistently across assets) from simple tags (freeform text labels) and contextual metadata (unstructured per-asset key/value pairs)
3. When uploading or updating an asset, pass the `metadata` parameter as field-name/value pairs matching your defined structured fields, and pass `tags` separately as a comma-separated or array list
4. List existing metadata field definitions via the Admin API before writing values, so you can validate values client-side against enum/datasource constraints and avoid write failures
5. Use the Search API's metadata- and tag-based expressions to query assets by the structured field values or tags you've applied