Design: a forge births a forge — new org, instance, chosen apps, crew, domain, keys — and the child follows its parent; '+ New forge' #389

Direction #334 §6 and the owner's intent: apps can leave to an entirely separate forge; a forge can be dropped for a client with custom apps ready ('an organizational operating system tailor made'); every deployed forge should see its upstream (take updates, propose back, appear in the family tree). Today following is fork→parent inside one forge only; a forge can already run as an app inside another (hosted mode: no SSH, one agent at a time).

Planner: write the design as linked issues — the spawn action (what is copied: apps as repos, crew briefs, subscriptions? never the parent's secrets), the child's first boot (direction, tokens, domain), cross-forge following (child reads parent releases and takes updates; proposes upstream; family tree across forges), the '+ New forge' door in the studio, and where a child body runs (hosted inside the parent today; the tofu spike #339 decides Cloudflare/Fly/metal). Waits for #383 (planner loop fix) and the tofu spike.