Resume abandoned interviews across any channel

• Idle interviews now resolve automatically into Complete or Partial after a configurable timeout per research, so abandoned conversations stop hanging in progress.
• Participants can resume or restart abandoned and ended interviews across web, Slack, and WhatsApp with a clear Continue or Start Over choice.
• New per-research setting to remove Perspective branding across the interview UI, emails, embed sign-in, and previews.

• Refined messaging, timing, and researcher insights for partial interviews (previously called "abandoned") across email and Slack.
• AI tool error states now use a calmer neutral style instead of alarming red.

Branded email previews now reflect the remove-branding setting immediately instead of showing stale content.