The boot is now ONE DAG, assembled inline in submit_boot_tree — no boot_root
Noop anchor, no per-agent child DAGs, no display-only parent_id grouping: a
sweep MetaLock root (only when something is stale) that grows one rebuild
subgraph per stale agent into the same DAG (via append_subgraph, previous
commit), plus one Reconcile root per drifted agent (independent — a boot
reconcile needs no lock bump).
- submit_boot_tree builds the DagSpec inline; removed the single-use
templates::{boot_root, startup_sweep} builders (inlined per the operator's
"don't force single-use shapes into templates.rs" steer).
- fanout_specs simplified to the meta-update cascade path only — the startup
sweep no longer fans out child DAGs, so its branch was dead.
- test: append_subgraph_roots_on_emitter_and_rebases_local_deps.
Vestigial after this (deliberately left as follow-ups, flagged in the PR):
NodeKind::Noop is now unconstructed (contained to hive-c0re, removable);
Template::StartupSweep is unconstructed but a hive-sh4re wire type
(frontend-coordinated removal).