First subagent gets a horizontal 60/40 split (main left, agent right).
Subsequent subagents split vertically within the right column so they
stack. rightColumnPanes tracks right-column pane order so each new
split targets the last pane in the stack.
- plugins/tmux-panes.ts: opencode plugin that hooks into session.created/
session.deleted events to spawn a tmux pane per subagent running
'opencode attach', giving live visual TUI for each background agent
- opencode.jsonc: load the local plugin alongside @tarquinen/opencode-dcp
- skills/tmux-session/SKILL.md: teach agents to manage persistent tmux
sessions (dev servers, watchers, worktree windows) with oc- naming
- c.fish / cc.fish: auto-start a tmux session when invoked outside tmux
so the visual panes plugin can always activate
