Persona Creator: improvements, and save at the end

[enricoros]

Highlights of the existing persona builder:

• The quality of the Persona is actually Great! ✅
• The generation and UI is acceptable

Todo:

• UI could get some love
• UI could allow for "paste your text here" to generate a persona Persona Creator: From Text #282
• Persona is not saved at the end
• Generation can time out because it's using non-streaming generation APIs

Improvements

1. Save the persona at the end (may require Personas: Add custom, dynamic, and persisted #35 )
2. Use streaming APIs (see the Diagram generator implementation) to avoid network timeouts on edge functions, and show progress

[enricoros]

Streaming API just landed, even on stable, as it was largely requested.

[enricoros]

Closed by #301