Update an existing context.

To update a context, you must provide the contextId, which is the unique identifier returned in the response of the 'Create context' endpoint.

The context will be completely replaced with the new content provided in the request body.

Constraints:

• At least one instruction is required
• Each instruction text must not exceed 2000 characters
• Instructions cannot contain HTML tags or URLs
• The total content size must not exceed 50KB