Captures the decision to adopt @ai-hero/sandcastle as the orchestration
substrate for agent-driven development in this template. Records the
8-point decision (workspace dep, .sandcastle/ prompts, Dockerfile,
dispatch.mjs orchestrator, planning vs execute modes, generator-first
reviewer check, bring-your-own-key, per-task max-attempts), the four
alternatives considered (bare CLI / Copilot Workspace / custom-from-
scratch / no orchestrator), and four trade-offs (external dep, token
cost, Docker dependency, manual state mutation in v1).
Surfaces the decision at the top of README.md and AGENTS.md so new
contributors see the agent-driven framing before they hit the package
map or daily commands.
