Send a form entry (public)

Called from a form on a website by form.js (<script src="https://api.hypamoon.com/form.js" defer></script>); you rarely call it yourself. Needs the project's public token in ?token= (the same token as the chat widget, from POST /chat-tokens), an Origin header in its allowed_origins, a collection with access.public_write, and always a bot token from GET /public/challenge in turnstile_token. Limits: 30 entries per hour per IP address and 500 per day per collection. The response contains the id and created_at, never the data. If the honeypot is filled in, the response is the same but nothing is stored. The collection's triggers fire as they do for the API.