Publish podcast episodes programmatically via the Transistor API

Steps

1. Authenticate all requests by including your API key in the 'x-api-key' HTTP header — obtain the key from your Transistor account settings; the API follows the JSON:API specification and returns JSON-encoded responses
2. Create a new episode by POSTing to '/v1/episodes' with a JSON body containing at minimum 'show_id' (your podcast's Transistor show ID), 'title', and 'audio_url' or by uploading audio separately using the audio upload endpoint
3. To upload audio, POST to '/v1/episodes/{id}/audio_upload' with a multipart/form-data body containing the audio file — the endpoint returns an upload URL or accepts the file directly depending on your plan
4. Set episode metadata in the create or update call: 'summary' (plain text description), 'description' (HTML-formatted show notes), 'number' (episode number), 'season' (season number), 'type' ('full', 'trailer', or 'bonus'), and 'explicit' (boolean)
5. Publish the episode by sending PATCH to '/v1/episodes/{id}/publish' — this endpoint accepts a 'published_at' field for immediate publishing (leave empty) or a future ISO 8601 datetime for scheduled publishing; set to a past datetime to backdating
6. Retrieve episode status and published feed URL via GET '/v1/episodes/{id}' — the response includes 'status' ('draft' or 'published'), the public audio URL, and the episode's page URL on your Transistor site