Redesigned live stream creation flow

The “Create live stream” flow has been redesigned so configuration is easier to find while the stream is being set up.

• DVR mode (with inline tooltips explaining each option), expected duration, and reconnect window are all visible from a single screen.
• Simulcast destinations and playback policy (public/private/signed) can be configured during creation.
• Successful creation now auto-redirects to the new stream’s detail page with the embed code and stream URL already populated.
• Validation surfaces immediately as toast notifications instead of inline form errors that were easy to miss.