[codex] fix(dev): avoid focusing created restart tmux window

[miaoz]

Summary

• Create the missing dev supervisor window in detached mode.
• Insert it after the target session instead of making it the current tmux window.

Why

scripts/restart.sh status/start/restart calls ensure_target() before sending keys or capturing output. When the ccgram tmux session already exists but the __main__ window is missing, tmux new-window currently creates that window and makes it current for attached clients.

That can steal focus from whatever window the developer is actively using in the same tmux session. Using new-window -d keeps the current window unchanged while still creating the target window for subsequent send-keys and capture-pane calls.

Validation

• bash -n scripts/restart.sh