One round-trip to create many nodes

Anything that lands a plan of nodes — installing a course's exercises into your own space, importing a module, seeding a workspace — used to issue one create request per node, each paying its own round-trip through the mesh. Copying a course of a few dozen subtrees took minutes for that reason alone.

The mesh now has a bulk create verb: one request carries the whole plan, every node is validated and permission-checked up front (a refusal writes nothing at all), and the batch lands in one ordered storage write with every downstream reader notified node by node, in order. Nodes you already have are skipped and reported, never overwritten — and everything that deliberately stays per-node (access grants, satellites, updates) keeps its careful path.