CSV export

You can now export your entire waitlist as a CSV — one click from the dashboard, or a single API call.

What's included:

• Dashboard: an Export CSV button on the waitlist page downloads the file directly via your browser session. No API key needed in the browser.
• API: GET /v1/waitlists/:id/signups/export streams the full signup list as CSV. Useful for piping into scripts or external tools.
• SDK: waitlists.exportSignups(id) returns the CSV as a string.

The export streams in batches so it won't fall over on large lists. Values that could trigger formula execution in Excel or Google Sheets (starting with =, +, -, @) are sanitised automatically.

The SDK bumps to 0.2.0 with this release.