Introduce internal commands to manage execution state

[joshi4]

• cmd/internal: setup internal cmds
• parse params
• server/client: Create client for any socket path
• server: DRY cleanup socket committed
• client: Add a shutdown interface
• server/run: Add a run server
• savvy.zsh: only use zle to trigger runner
• server/client: SendShutdown returns an err
• server/run: Update state based on commands
• server/run: Add client for run server
• cmd/run: use runServer to coordinate state
• server/run: disambiguate client struct from pkg
• cmd/internal: impl current and next
• change return data for next and current
• cmd/history: handle err starting record server
• run: start server
• server/run: read json messages instead of waiting for client to close the conn
• close client conn when done
• savvy.zsh: use internal commands to run runbooks
• cmd/next: return immediately if no prev command
• server/run: return val using json encoder
• server/run: allow idx == len(commands)
• debug: savvy.zsh display next
• add tests
• setup/savvy.zsh: use 0 based arrays everywhere except when displaying step count
• internal/next: return 0 based array idx
• server/run: rm debug logs
• setup/savvy.zsh: cleanup debug logs
• server/run: Add note about why the run server is single threaded
• cmd/setup/bash-preexec.sh: impl run hooks with savvy internal cmds
• cmd/write: dracula shows better on light terminals