Pane input can be accepted without executing in a fresh `--no-focus` workspace after restore

[mattleong]

Is this a reproducible bug?

• I confirm this is a reproducible bug, not a feature request, idea, question, contribution proposal, or direction check.
• I reproduced this bug on the version and environment reported below using the exact steps provided.

Current behavior

After restarting Herdr and restoring my existing default session, a fresh workspace created with --no-focus can have a running zsh child but no readable terminal output. pane run, pane send-text, and pane send-keys return success, but the submitted command does not execute; pane wait-output times out and pane read remains empty.

I reproduced this on three consecutive disposable workspaces. It is stateful/intermittent: after activating a disposable workspace, later fresh-workspace probes sometimes succeed. The server log contained no error for the failed input calls.

Expected behavior

A pane returned by workspace create should execute accepted input independently of whether its workspace has been focused. Otherwise the input call should return a structured not-ready or delivery error rather than success.

Reproduction

1. Restart Herdr with its client attached and allow an existing multi-workspace default session to restore.
2. From another terminal, run:

created=$(herdr workspace create --cwd "$PWD" --label input-repro --no-focus)
pane=$(printf '%s' "$created" | jq -r '.result.root_pane.pane_id')
workspace=$(printf '%s' "$created" | jq -r '.result.workspace.workspace_id')
trap 'herdr workspace close "$workspace" >/dev/null' EXIT

sleep 1.5
herdr pane run "$pane" "printf '%s%s\\n' HERDR_ EXECUTED"
herdr pane wait-output "$pane" \
  --match HERDR_EXECUTED --source recent-unwrapped --lines 40 --timeout 5000
herdr pane read "$pane" --source recent-unwrapped --lines 40

Observed on failure:

pane run: exit 0, no stdout or stderr
pane wait-output: {"error":{"code":"timeout","message":"timed out waiting for output match"},...}
pane read: exit 0, empty output

The split marker ensures the echoed command cannot satisfy the match; only executed output contains HERDR_EXECUTED.

Impact

Background automation cannot rely on successful pane input. My subagent launcher must causally attest a sterile environment before starting a model, so every affected launch times out, rolls back its workspace, and never starts the agent.

Environment

• Herdr version: 0.8.0 (protocol 19)
• Update channel (stable or preview): stable
• Operating system: macOS 26.6, arm64
• Terminal: Ghostty 1.3.1
• Shell, if relevant: zsh
• Relevant config, if any: default persistent session with restore enabled; approximately 11 workspaces / 27 panes when first reproduced