## Why
A failed shell snapshot capture was cached for the lifetime of its cache entry, so later commands continued using the original command even after a transient profile error was fixed.
## What changed
- Retry failed captures after a one-second backoff, up to three total attempts.
- Share each attempt across concurrent requests and preserve command fallback during failures and backoff.
- Keep the final failure cached after the retry budget is exhausted.
## Testing
Cover recovery and retry exhaustion for concurrent requests, local and remote execution, pipes and TTYs, and Bash and zsh where available.
GitOrigin-RevId: b432ef7c9eb35a3a0a703ac675b4db6954c43a80
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