Resolves conflicts with the shared-checkout parallel rewrite (#607) and the
cached-run/billing dedup (de60eb900):
- handler/parallel.rs: rebuilt on main's shared-checkout version. Branch
ordinals are still reserved inside the branch task right before
ParallelBranchStarted (with graph_visit/resumed_from_stage_id), and the
reserved StageScope is shared with post-await error paths via a OnceLock
slot instead of main's dispatch-time visit=1 scope, so completion events
are never emitted under a guessed ordinal.
- billing.rs: keep this branch's run_stage_from_projection (RunStage grew
graph_visit/resumed_from_stage_id and a typed id), adopt main's
state.cached_run() and drop the removed run_stage_from_stage_id import.
- run_projection.rs: adopt main's typed parallel_results
(Option<Vec<ParallelBranchResult>>).
- run_event/misc.rs: union of both sides' imports.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
eb83539a18