Data-authorability boundary — folds, composites, construction args
One boundary question — where data authoring ends and Rust authoring begins — at three vocabulary sites, each needing its own mechanism. Domain invariant 10 wants native-Rust authoring as the escalation path for genuinely new logic, not the convenient path for composition or config; the 2026-07-22 external field test (triage: #314) showed the opposite pull: the agent wrote native nodes for four-node patterns fully expressible in the shipped vocabulary. #271 is the settled end of the boundary: non-scalar structural construction config (Session timezone/open-time) was ruled data-authorable at the user's request (2026-07-14, recorded in the issue); its typed construction-args mechanism remains to build. #310 (per-tap fold/Live subscription selection: ratify Rust-only, or add a data selector) and #317 (a named, registered composite subgraph referencable like a node) are the two still-open forks of the same boundary; deciding them together against the #271 precedent keeps the ledger ruling consistent instead of drifting per site.
Done: the boundary is recorded in the ledger for all three sites, and each site's mechanism (or ratified Rust-only status) conforms to it.
