Snapshot-aware GROQ for instanceId — runs against the same
in-memory view the engine's filters see, with the caller-free
rendered scope auto-bound: every always-bound condition var,
$fields with the open stage's overlay merged, $assigned at its
caller-free false, and the author's pre-evaluated $<predicate>
booleans, ids in GDR URI form. Use to ask "what does the engine see
for this workflow?" — useful for filter debugging, UIs that mirror
engine state, etc.
Run an arbitrary GROQ query through
workflow.query. The query MUST filter on the auto-injected$tagparam (e.g.*[... && tag == $tag]) or it throws — the engine refuses to run a query that could read across partitions. Caller is responsible for narrowing the result.