Setup Sandcastle

Repo/code changes: run /deslop before commit, push, PR, or merge. Sandcastle orchestrate agents in sandboxes with branch strategies. Two modes:

• run() -- headless (--print), stream-JSON parsed. CI, batch, overnight.
• interactive() -- full TUI passthrough (stdin/stdout/stderr). Human watch + intervene. HITL review, pair-review, local dev.

Both modes: hooks fire inside each session. Dev lifecycle enforced regardless of launch method.

Capabilities: task picking (GitHub issues -> one agent per issue), parallel N agents in isolated sandboxes, HITL review with full TUI, noSandbox() for git worktrees only, hooks in each session, branch strategies (head, merge-to-head, branch).

Builder.io helper defaults: run /stay-within-limits before large batches and between waves, use /efficient-frontier for bounded delegation packets, and audit returned branches/sessions with /agent-watchdog before merging.