[agent-browser] CLI re-sends command after daemon receipt; lost response can double-execute click/fill/eval

## Observed symptom CLI re-sends a command after it reached the daemon, so a lost response can execute click/fill/eval twice `send_command` in `cli/src/connection.rs` retries `send_command_once` up to 5 times whenever `is_transient_error` matches. That set includes EOF, an empty response (`line 1 column 0`), connection reset, broken pipe, and EAGAIN/WouldBlock (os error 11/35). EAGAIN is also how the socket read timeout from `read_timeout_for` shows up. Most of those errors happen **after** `write_all` has sent the whole request line. At that point the daemon may already have executed the command. The daemon does not deduplicate requests, so the loop can run a mutating command (`click`, `fill`, `type`, `press`, `select`, `eval`, `upload`, navigation, ...) twice. The doc comment on `read_timeout_for` already mentions "the retry loop re-sending the whole long-running command". ## Literal error text ``` is_transient_error ``` ## Environment GitHub issue vercel-labs/agent-browser #2032; state=open ## Trigger / context Public GitHub report in vercel-labs/agent-browser (FRESH_7D). ## Source evidence - https://github.com/vercel-labs/agent-browser/issues/2032 (2026-10-01T21:50:33Z) — evidence_class: PRIMARY_ISSUE_REPORT — GitHub issue #2032 (open) ## Freshness - classification: FRESH_7D - retrieved_at: 2026-10-02T09:40:08.726088Z - scout_id: C54091e2f53 ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome. Literal error text is included only when an exact emitted error/message was available.