Purely mechanical: src/core/contracts/{plan,graph,chat,jobs}.ts carry the
sections verbatim (graph = nodes + ledgers + extraction findings; jobs =
the async ack-and-steer protocol + tool results + demo bridge), and
contracts.ts becomes a re-exporting barrel so every existing import path
(@/src/core and ./contracts.ts) is unchanged.
Wave-2 lane ownership follows the split: the graph stream owns
contracts/graph.ts, the teacher stream owns contracts/jobs.ts — same-file
contract collisions between streams are structurally impossible now;
cross-domain schema changes go through master.