Retry and auto-retry

Overview

Failed turns get two recoveries. Every inline error card in a chat now
carries a Retry button that re-sends the failed user message. A
per-chat auto-retry toggle additionally re-sends a message once,
transparently, when it fails before a response starts (a network error
or an HTTP rejection other than an already-running 409).

Usage

Manual retry

• Send a message that fails. The red error bubble in the transcript
  includes a Retry button.

• Retry re-posts the same user message the model was working on. The
  failed response stays visible above the new attempt, so nothing is
  silently discarded.

Auto-retry

• Open a chat and tap the tools button, then toggle Auto-retry failed
  sends in the footer.

• The app-level default lives in Settings → App defaults, where it
  defaults to on. A per-chat choice overrides the app default.

• When a turn fails before any response starts, the client immediately
  resends it once and shows an auto-retrying… status. Retried sends
  are themselves never auto-retried again, so a persistently failing
  message cannot loop.